Breeding tropical marine fish

pair of clownfish breeding

How to start breeding tropical marine fish

pair of clownfish breeding
pair of clownfish breeding

If you have been successfully keeping saltwater fish in a marine tank for a while then perhaps you would like to move on to breeding your fish.
Many keepers of saltwater aquariums are content to just keep fish. For the brave few I will outline the basic steps that you need to be take in order to ensure a healthy brood. I will assume that you are familiar with the basics of marine aquarium care.

Feeding saltwater fish here

Saltwater aquarium maintenance here

Marine corals here

Equipment and food for breeding marine fish

Besides having a male and female fish, you will need to do some preparation for your fish if you would like to enjoy successful breeding:

• Breeding tank—You will want to setup a separate bare-bottom breeding tank that your fish larvae can comfortably live in until they become adults. It may help to have several tanks ready, depending on the size of the brood you plan on keeping. Large filtration is out of the question, but a simple air stone can help keep the water moving.

• Live food cultures—Fish fry will thrive if they given a continuous supply of live food. You will want to begin preparing your live food cultures before breeding starts so that you do not have to rush after your fish have bred. It is recommended to culture both rotifers and baby brine shrimp as the best two starter foods.

Many saltwater fish will begin their lives in a larval state, which often requires the set up of complex larval rearing systems in which multiple breeding tanks are connected to the main tank through a sump and constantly fed rotifers and live food cultures. If you are breeding your first tropical marine fish, it is advisable to choose fish that you can raise in a simple breeding tank without having to worry about the larval phase.

Selecting which marine fish to begin breeding

Since some marine fish require such a complex breeding set up, you, as a beginner, should focus on breeding easier species of saltwater fish that are simpler to breed. Avoid breeding fish that have a “pelagic larval phase”. The following list of fish have fry without a protracted larval phase.

male banggai cardinalfish brooding a mouthfull of young fish
male banggai cardinalfish brooding a mouthfull of young fish

• Banggai cardinals,
• Clownfish,
• Bristletail filefish,
• Green wolf eels,
• Neon gobies,
• Dottyback fish.

If you have a healthy pair of any of the above species in your tank, you can reasonably expect them to breed at some point. Most saltwater species will breed on their own when kept in excellent water conditions. However, certain species may take a long time to form a sexual pair.

If your fish are just not breeding despite keeping excellent water conditions with lots of hiding places then try moving your pair of fish into a low-light spawning tank. Orchid dottybacks, for instance, will breed readily when paired off in a small, covered tank with some decoration.

What to do when spawning begins

Generally, your job will begin when the eggs hatch. Up until then, one of the parent fish will usually defend their eggs, and will generally do a good job of it. Once the eggs hatch into larvae, however, you need to get them into a separate tank and get them fed.

Collecting your larvae from the main tank can seem like a difficult task, but one important tip can help: fish larvae tend to be attracted to light. To collect your larvae, follow these steps:

• Turn off the lights and water flow in your tank,
• Shine a small flashlight at the corner closest to the larvae,
• Let them accumulate in the light for a minute or two,
• Use a dip cup or siphon to collect them and deposit them in their own tank.

Raising the larvae of marine fish

Feeding the fry is the main stumbling block in reproducing marine fish. Many aquarists fail at this stage or lose all but a few of the fry. There is definitely money to be made for the aquarist who can successfully feed and raise a whole brood to a saleable size regularly.

Your fish larvae will need to be fed frequently and in large quantities. In the sea they would be surrounded by a rich variety of live plankton. Larval fish are voracious eaters and their appetite will surprise you. Moreover, their waste and waste of their live food will make frequent water changes necessary.

It is important to remember that your marine fish fry, being so small, will be unable to catch all of the food in the tank, and you will inevitably lose some food to waste and even some fish to starvation. These larvae need to have food within several millimetres of themselves in order to catch anything, which means saturating your tank with rotifers or plankton. Moreover these rotifers must be fed too. The rotifers must be fed with nutritious live algae. Ultimately this nutrition passes to the larvae via the rotifers. Algae can be raised with a light source and nutrient rich saltwater.

In fact, you may find that you are quickly running out of food to feed your fish, which leads to a very important rule: Never raise more fish than you can feed. You may have to cull some of the less fit members of the brood in order to realise this goal, but it will save the rest of them and ensure the health of the rest. A healthy minimum concentration would be 10-15 rotifers per millilitre of aquarium water in order to simulate the plankton they would find in the wild. A good system is to have and feed the rotifers in the same tank as the larvae. This, though, puts a heavier burden on the raising tanks oxygen demands and ammonia levels.

With frequent water changes, a well-oxygenated tank and lots of food, you should start seeing growth in your fish. The water changes will be very important since both your fish and your rotifers will cause ammonia levels to climb, and your filtration will be limited to fluidised sand filters, trickle filters and protein skimming – anything that uses greater flow will suck up the larvae.

Caring for your fish larvae

When breeding tropical marine fish, you will need to take care against bacterial infection. Siphoning out the waste properly twice a day should help reduce the risk of harmful bacterial colonies developing on decomposing organic waste. Your fish larvae have brand new immune systems that will not protect them from infection.

Protein skimming, again, can help greatly here by removing organic material and bacteria from the water column. A UV steriliser is also a very good idea for your breeding tank. If any of your larvae get sick, they need to be culled immediately to protect the rest of the brood.

aquarium bred two month old clownfish
aquarium bred two month old clownfish

Once your fish are large enough, you can begin feeding them baby brine shrimp as they gradually mature into juvenile fish and become ready to be weaned onto a diet of dried foods. While rotifers are ideal for the very beginning, eventually your fish will grow too large to be effectively fed by these tiny organisms.

One last important thing to consider: Since your larvae respond to light by moving towards it, any light source outside the glass of your aquarium will attract them. The result of this is that it will cause your larvae to bump their heads against the aquarium glass until they die. This behaviour also occurs if the larvae have run out of food. To prevent this you will need to cover your aquarium’s bottom and sides with a dark material.

If you have followed these instructions and researched the needs of your individual species, you will be well on your way to successfully breeding tropical marine fish for the first time!

low maintenance fish keeping

three year old Walstad aquarium

A guide to low maintenance fish keeping

three year old Walstad aquarium
three year old Walstad aquarium

Why create a low maintenance aquarium? So you can spend more time admiring your fish, perhaps. People who are just getting started in the aquarium hobby are often taken aback by the level of maintenance that a successful fish tank usually needs. The cultural stereotype of keeping a goldfish in a tiny bowl and enjoying some kind of no-maintenance pet that just floats around and nibbles on flake occasionally is quickly dispelled once the conversation turns to biological filtration systems, cleaning schedules and balancing the nitrogen cycle in your tank.

It should come as no surprise, then, that many fish keeping enthusiasts have come up with some clever ways to lower the maintenance needs of their tanks. Thanks to one of two approaches, aquarists are getting closer than ever to a no maintenance sustainable environment that does not need constant upkeep and vigilance to keep their fish healthy.

Two approaches: natural and high-tech

If the average aquarium maintenance seems like hard work then there are two basic ways to approach your setup in order to enjoy a tank that allows for low maintenance fish keeping:

natural tanks-These tanks are designed around sound ecological principles. While complex these greatly reduce the amount of work that you have to put in on a regular basis. These tanks focus on providing a closed ecosystem that is as close to natural as possible, with plants, algae, bacteria, microscopic planarians, freshwater shrimp, and fish completing the food cycle for you.

High-Tech tanks-This kind of aquarium does away with the need for ecological purity and uses automation and chemicals to maintain comfortable water conditions without your help. This means using sterilisers,  over-filtration, automatic feeders, algae-reducing chemicals, and more. These tools work in concert to keep the tank healthy and clean.

In natural tanks you will want to plan your tank around hardy, low maintenance fish that can tolerate the occasional change in water quality without being too badly shaken by the experience. Natural tanks will have occasional biological issues, and high tech tanks may suffer malfunctioning equipment from time to time, so it is important that you do not commit yourself to extremely delicate species.

Designing a natural tank

newly set up Walstad aquarium
newly set up Walstad aquarium

If you would like to set up an natural aquarium for low maintenance fish keeping, your tank will need to put a premium on long term planning and maintaining adequate life cycles for all of the tank’s inhabitants. Your choices regarding the species that you would like to keep will be very important, since they will all need to work together in order to maintain a healthy tank.

In the case of a natural, self-sustaining aquarium, the simplest aquarium tools can be put to effective use while plants and bacteria take care of your biological filtration needs. A drip-feed system can make water changes unnecessary, and with the right approach to your plants, you may even eliminate gravel cleaning from your to-do list, leaving you only with the responsibility of feeding your fish.

Plants are a necessity for the low maintenance fish keeping set up. By absorbing unwanted fish waste and keeping algae in check, they can help reduce the need for water changes while keeping your fish healthy. Good low-maintenance choices include the following:

  •  Water wisteria,
  •  Java moss,
  •  Lilaeopsis,
  •  African water fern,
  •  Java fern.

Simply keeping plants in your aquarium is not enought to ensure a stable low maintenance environment. Using soil as a substrate can allow biological filtration to occur directly within the tank when done properly. One of the most effective natural tank designs is the soil-based tank developed by Diana Walstad.

The Walstad Method

Diana Walstad has pioneered an unorthodox method of low maintenance fish keeping  that makes heavy use of plants and organic soil conditions to keep aquarium water healthy for fish. The combination of a soil substrate with fast growing plants takes out the nitrate and ammonia present in the water. This natural approach allows for filtration to occur through the land-based plants’ absorption of those chemicals in the roots and their subsequent release in to the atmosphere, above the water line.

These aquariums, when properly set up, can greatly reduce the need for mechanical filtration tools and other gadgets while also eliminating the need for you to personally change the water constantly. The key is to be found in the proper use of soil as a substrate rather than conventional gravel. Having your plants rooted in a thin layer of high quality soil allows anaerobic bacteria to filter the water without overwhelming their roots. This high quality soil boosts plants growth and activity. Thriving plants take out a lot more of the harmful ammonia, nitrites and nitrates than their struggling counterparts in a gravel tank. This also makes gravel cleaning a thing of the past.

With this kind of tank, supplemented by the addition of microscopic planarians or daphnia and other live food, you can enjoy a truly low maintenance fish keeping set up. You can do away with all the specialized equipment and other products. Often, a natural Walstad tank can be enjoyed indefinitely with only a heater, good lighting for the plants, and a light-duty mechanical filter or aerator that keeps the water flow up. The Walstad set up can be enhanced with a modicum of equipment, especially a small biological filter and a drip feed water system. But then it is not a 100% natural system.

You can buy Diana Walstad’s book on Amazon.The book goes into detail on how the aquarium ecosystem works. She details some of the experiments in building a sustainable ecosystem that have lasted several years. This is not a book full of pretty pictures. It is a book that will tell you how to build healthy and low tech aquariums where the plants thrive and the fish are healthy. Click on the book on the left to buy the book.

 

The value of high quality soil in an natural tank

Since it is clear that the use of soil as a substrate is what makes this tank special, it is important to determine what constitutes high quality soil and sets it apart from other options. The main concern here is to use properly natural soil—that is, soil that is made of 100% natural matter so that natural decomposition can take place.

The composition of the soil will greatly affect the water quality of your tank as it decomposes, so you will want to perform frequent water changes while your tank and its fish adapt to the presence of the soil and an ecological balance is created. Regular potting soil is largely excluded due to the presence of additives that will contaminate your water.

Step by step process for setting up a Walstad Method natural tank

• Start with your tank’s essentials: the heater and filter/power heads should be in place before you add anything else to the tank.

• Begin by adding a 3 cm layer of untreated, non-sterile top soil to the tank.

• Cover the soil layer with an additional 3 cm of medium fine gravel, or a fine layer of sand. Be gentle: too much covering will deprive your bacteria of oxygen.

• Your plants will need calcium. If your water is soft, add in bone meal or coral gravel to compensate.

• Add your choice of plants and turn on your lights: 2 watts for every 3.8 litres is a sufficient amount.

• Add clean room temperature water that is free of chlorine or chloramine.

• Use filters or power heads to maintain brisk water flow and keep the water oxygenated, especially until cycling is complete.

• Test for pH, ammonia, nitrate, and nitrite every two days for two months, changing the water as necessary. Some soils will require frequent changes to rid the water of toxins.

• You can add fish immediately after setting up, but be sure to perform 25% water changes as soon as you see ammonia or nitrite levels above zero.

• If algae becomes a problem, reduce your lighting or add floating plants to the tank. Once the tank is established, the plants will effectively out-compete algae for nutrients.

To read more about the techniques and why they work then read

The high-tech tank

If you would like to enjoy low maintenance fish keeping without making any compromises on fish choice or plant presence, the high-tech tank might be for you. This type of tank has a number of benefits, including the fact that you can keep just about any type of fish you desire, and plants tend to grow bright and beautiful quickly in this environment.

Some delicate fish species that usually live in river environments are especially suited to the high-tech tank. The increased flow, filtration, and continuously changing water will make river species feel right at home.

The main drawback to the high-tech tank is that setting it up is a long process. After set up there is usually a tinkering period where you fine tune things. You will have to invest a bit of time, energy, and money into maintaining a proper balance through technological means. This could mean using any or all of the following tools to keep the water conditions ideal for your fish:

• Double filtration—Using multiple filters will effectively double the period before you need to clean the filter media. Doubling the filters maximises biological filtration to keep ammonia, nitrate, and nitrite levels at zero.

• Power heads—These can help keep the flow rate high within the tank, enabling effective filtration and keeping detritus and mulm from settling into the gravel substrate. This gives more of a chance for the filters to pick it up instead.

• Drip-Feed System—This is a very useful DIY project that will continuously drain and replace water from your tank: Pre-filtered water is drip fed to the tank while an overflow system drains all excess water. Carbon filtration is needed to remove chlorine.

• Automatic feeder—A programmable fish feeder can store days’ or even weeks’ worth of food and reliably deposit a controlled amount directly into the water at regular intervals. Robust, high quality units can be left on their own for weeks at a time without worry. You can even go on holiday and not worry about hungry fish.

• UV steriliser—Low maintenance fish keeping practitioners still need to control algae, and if you want to avoid regularly scraping your aquarium glass clean then a UV steriliser will provide the algae control that you need.

• Algae-controlling chemicals—Another low maintenance fish keeping solution for controlling algae is through the use of specialized chemicals. These can be found at many fish and aquarium supply stores. But these are a last resort.

• Light timers—Choose your lights carefully to avoid encouraging algae growth. A light timer can also help by allowing you to set a specific lighting schedule that offers just enough to help your plants grow without triggering an algae bloom.

• Protein skimmer—Often found in saltwater aquariums, these devices greatly reduce the amount of organic fish waste in your tank, reducing the need for water changes.
This approach to low maintenance fish keeping allows you to enjoy your aquarium without needing to worry about your fish’s basic needs such as feeding and water changing. You will still need to perform regular cleaning. But with high-powered filtration of your tank and a good control of algae, you should be able to get by with a quick monthly vacuuming and filter rinsing schedule.

Step by step process for setting up a high-tech tank

• Again, start with the tank’s essentials: Your filters, heaters, and lighting setup should be ready.

• Add a 5 cm even layer of gravel along the bottom of the tank. If you use sand, a very shallow layer will make vacuuming easy.

• Plant any plants you may have now. If you use the easy-to-clean thin gravel substrate, your plants should be potted or attached to rocks and other decorations, which you can also add in now.

• Add clean, conditioned, de-chlorinated water to your tank.

• Insert and activate your filter, lights, and heater.

• Begin cycling either by adding starter fish, fish food, or another ammonia source.

• After cycling begins, you can activate the drip-feed system for constant water changing, though you may need additional water changes until cycling is complete.

• Test the water every two days for two months, waiting for ammonia and nitrate readings of zero.

• Respond to algae growth with reduced light until cycling is complete. The UV steriliser and protein skimmer should help here but if it is not enough, you can add algae controlling chemicals after cycling is complete, or even use low maintenance floating plants to control algae growth.

Once you’ve successfully cycled your tank, you should have a complete low maintenance fish keeping solution on your hands: high water flow, drip feeds, and automatic fish feeders will ensure that your aquarium stays sustainably healthy without constant care. Again the high tech system is enhance by having floating plants and biological filtratrion. So not a pure high tech solution.

Now you can sit back, relax and enjoy your fish. You’ve earned it.