Your first saltwater aquarium: Step by step guide

Typical beginners saltwater fish tank set up

Your first saltwater aquarium: Step by step guide

Marine fish such as the azure damselfish have the best colours

Buy and assemble all the equipment

Equipment you will need

  • A 120 litre 4 foot tank. This is a basic minimum size.
  • Buy a hood with a normal lighting system.
  • You will also need a protein skimmer,
  • An external power filter,
  • 300w heater,
  • A thermometer and hydrometer to measure the salinity,
  • Good beginners fish pajama cardinalfish
    Good beginners fish pajama cardinalfish

    A marine water test kit

  • Bag of seawater salt mix
  • Natural coral sand
  • Fish tank stand.

Inhabitants for your saltwater fish tank

  • 10 kilos of live rock
  • 1kg Live coral sand
  • 10 margarita or asteria snails
  • 2 hermit crabs blue or red-legged
  • Some hardy peaceful fish species

Find out more about live rock and live sand here.

List of beginners recommended saltwater fish

Preparing your first saltwater fish tank

Live rock with coral sand in a beginners saltwater aquarium
Live rock with coral sand in a beginners saltwater aquarium

Put together your stand and aquarium. Wash the inside of the glass with warm water. Never use any chemicals or soaps. If there are any stubborn stains then use white vinegar and a razor blade to scrape the stain. Rinse any white vinegar with tap water. Remove water with a siphon hose. Paint the rear glass in black, blue or marine or apply a stick on background.

With the tank empty move the stand and tank around the room until you find a location you are happy with. You can use a spirit level to adjust the levelness of the aquarium. If the aquarium doesn’t sit level then you can use thin flat pieces of plastic or wood to raise the leg that is lower. Once the aquarium is sitting level then you can then fill with water. Once the aquarium is 95% full then again check the aquarium for levelnbess. If the aquarium is not level then you will have to remove all the water and adjust the levelness again before re-adding water.

Once the tank is 95% full of water and level then you have to wait 24 hours to see if any slow leaks occur. If there are no signs of any leaks then install the filter, heater and protein skimmer. Set the heater to 76 Fahrenheit.

Plug in all the equipment and switch on everything. Leave everything running overnight. The next day check the temperature to be 76F. If the temperature is out then you have to adjust the thermostat.

How to get the salinity right for your saltwater aquarium

Royal gramma is a hardy fish but can be a little aggressive
Royal gramma is a hardy fish but can be a little aggressive

Calculate the volume of your aquarium then add your sea salt mix according to the recommended amount on the bag of your mix. If you wait another 4 hours your salt will have completely dissolved in the water. You can then check the salinity of the water with your hydrometer. The reading should be between 1.022 to 1.024 when the temperature is 76F. If it is less then you can adjust by adding a little sea salt mix. If it is more then you can reduce it by adding a little fresh water. Thenm wait a further 4 hours before testing again. When you achieved your ideal density use a black marker to mark out the water level in a hidden part of the glass. This mark will be your guide to the level of water before any evaporation. Topping up back to this level should get you back to the correct salinity.

Now test the water’s ph. It should read 8.2-8.3ph or close to this. If it is far from this then you’ve done something wrong somewhere or your hydrometer or thermometer is wrong. Fix the problem by changing your hydrometer or thermometer and make adjustments. If there is still a misreading then you will have to switch everything off and remove all the water and start again with the water mix.

Adding live rock to your saltwater aquarium

golden wrasse - perfect lemon yellow fish
golden wrasse – perfect lemon yellow fish

When the water is just right you then need to start adding your pieces of live rock. Start with the larger pieces first. Move the rock about to create a pleasant aquascape. Test each piece is stable by prodding and adjusting into a settled position.

Place the bigger, heavier pieces directly on the glass. These should be arranged in a long semi circle along the sides and back. Leave gaps in between the individual pieces of live rock for your fish to swim through. Place the smaller pieces of rock in front of or even on the larger pieces again making sure that the whole setup is table. Use the live rock to hide the heater and protein skimmer behind.

Adding coral sand to your saltwater aquarium

You should clean your sand before you put it in the aquarium. All you need to do is rinse it thoroughly in a bucket of water by running the water through a bucket of some sand. Do it in small batches of sand and swirl the sand round until the water runs clear. Remove the water from the backet and put the sand into the aquarium all along the floor of the aquarium around the live rock.

Once the sand has been added the average level should be 2 inches deep. Then take your 1kg of live sand and spread it evenly over the other sand. Do not wash the live sand. It should contain beneficial bacteria and life forms which you risk killing by washing with tap water.

Check all your water measurements again such as ph, salinity and temperature. Adjust if necessary.

Adding background creatures to your saltwater aquarium

blue legged hermit crabs cleanup crew
blue legged hermit crabs cleanup crew

After a week add your first creatures. Remember your filter, heater and skimmer should be running continuously throughout this time. Add your snails and hermit crabs. Algae eating species are recommended to clean up any algal blooms that usually break out in new saltwater aquariums. You should not just throw your snails or crabs directly into the water but float the bags in the water for 15 minutes then add some aquarium water to the bag slowly over ten minutes before releasing them into the aquarium.

Feed the snails and crabs with tiny amounts of fish food as a top up to the algae that the snails and crabs may eat, which may be insufficient for their needs.

Adding your first fish to your saltwater aquarium

yellowtail-blue-damselfish may not be the perfect 1st fish
yellowtail-blue-damselfish may not be the perfect 1st fish

More on clownfish types

More about clownfish

More on Damselfish types

Some experts recommend adding a couple of damsel fish as your first fish because they are a tough fish and can cope with the conditions while your aquarium water is cycling. While this is true I recommend an alternative to damsels as a first fish such as tank bred clownfish because damsels can be aggressive to future fish additions. You can start off with just a couple of clown fish to add colour and interest to your tank.

During this time your aquarium filter and live rock will be cycling by developing a colony of bacteria that can digest fish and other creature waste products turning it into less harmful nitrate. This process can take anything from 4-8 weeks. During this time there will be an excess of ammonia and nitrite which are harmful to your fish and other creatures.

Complete your saltwater reef aquarium set up

orchid dottyback is the least aggressive dottyback
orchid dottyback is the least aggressive dottyback

After your first fish have settled in and looking healthy and happy you can start adding some invertebrates and a few other fish. Add hardy species of anemone. A good choice of anemone are feather dusters.

Fish to consider at this point will be wrasses, dottybacks and banggai cardinal fish. Try wherever possible to buy tank bred fish as these are fish that have adapted to life in the aquarium and should prove better survivors in your saltwater tank. Add fish at a rate of 1 or 2 a week. When you add new fish keep a close eye on them and make sure the newly added fish start feeding within 2 or 3 days. Also check the nitrite and ammonia levels daily. Stop adding new fish if the readings rise.

Some fish and other creatures to absolutely avoid as a beginner are: seahorses, octopuses, angelfish, clams, scorpionfish, and damsels.

When you have a settled tank and have introduced all the fish and other creatures for your aquarium then you can reduce the water testing to once a week.

Now you can sit back and enjoy your own piece of the ocean in your living room. However, you still need to keep checking all your water parameters once a week at least or when something doesn’t look right with any of the inhabitants.

Aquarium pests

An aquarium blighted by algae

How to control aquarium pests

An aquarium blighted by algae
An aquarium blighted by algae is an eyesore

Your aquarium is very similar to a carefully-tended garden in many ways, especially when it comes to unwanted pests that can accumulate, often rapidly, and begin causing damage to your delicate aquatic ecosystem. There are numerous types of aquarium pests and fish parasites that, if left unchecked, can seriously affect the health of your fish and even kill them.

Some of the most common pests that you will find in a typical tropical aquarium are as follows:

  • Algae – This is by far the most common pest, and it comes in many flavours: brown algae, hair algae, bubble algae, slime algae and more. Most of these are easily controlled by addressing your tank’s water quality and level of light exposure. Though not harmful to your fish, it is unsightly.
  • Snails – These small creatures can suddenly appear in your tank, where they will begin to eat your live plants and reproduce rapidly. If left unchecked, they will push your tank’s biological load far past its limit. They also eat fish eggs.
  • Hydra – Tiny freshwater polyps that like to feed on fish fry, Hydra can be very difficult to eliminate from your tank once an infestation begins. They can also irritate larger fish and are generally unwanted even if you do not have fry present.
  • planaria can be a nuisance and are an indicator of a dirty aquarium
    planaria can be a nuisance and are an indicator of a dirty aquarium

    Planaria – These creatures occur as a result of overfeeding or bad water management. Although not harmful to fish, though they may irritate the fish, they are unsightly and are a sign that the aquarium is not well cared for.

  • Floating Plants – If left to grow unchecked, floating plants can become a nuisance and need to be trimmed down to size.

How aquarium pests get introduced to your aquarium

The one major difference between your fish tank and a garden is the fact that your aquarium, at least in theory, is a closed ecosystem. You may be asking yourself how aquarium pests occur in such an environment: Most commonly, they are introduced as eggs, larvae or pupae on rocks, driftwood, and other aquarium decorations that have not been thoroughly cleaned.

The most effective way to prevent most of these pests from invading your aquarium is to carefully clean anything that you introduce to your aquarium. Snail eggs can ride in on live plants, or even with newly bought fish in some circumstances, which makes absolute prevention impossible. Pest control is occasionally still necessary, however. Another sure way is to absolutely avoid adding new objects, plants and fish to the aquarium.

What to do about aquarium pests in your tank

By far the most common pest is unwanted algae, which is relatively simple to control. New aquariums are particularly vulnerable to brown algae, which will usually go away on its own after the aquarium becomes properly established. Regular water changes and a strictly controlled lighting set up will discourage algae from growing, as will the introduction of plants to your tank.

Algae grows as a response to certain wavelengths of light. If your lights are old the wavelength changes, which may encouraging algae growth. If you continue to have problems despite using the correct lighting, it is a sign that your water is saturated with nutrients. A protein skimmer can help remove the organic waste that algae feeds on. A reverse osmosis water filtration system can remove nutrients before they enter the aquarium. Another option for immediate control is blocking out all light entering your aquarium for a few days.

Snails can be controlled by a variety of means. You can crush the shells yourself and let the fish eat their remains. Or add a snail-eating loach to your tank. You can also buy assassin snails which will hunt down and eat your snails reducing the number of snails. Another way to reduce the snail population is by adding copper to your water, which is a toxic substance for most aquatic invertebrates. Small copper coins can work, although they must be cleaned before introduction to the tank.

When it comes to hydra, the problem can get a bit more complicated. Chemical solutions exist, but can be harmful for live plants, fish and the beneficial bacteria in your filter. A better way to control these creatures is through the introduction of hydra-eating fish like three-spot blue gouramies. If that is not an option, you will have to cook them.

hydra catching daphnia. hydra is a threat to fry
hydra catching daphnia. hydra is a threat to fry

Hydra will die at a temperature greater than 40°C, which is less than what would kill your beneficial bacteria, so if you temporarily remove your fish and raise the heat to this temperature for a few hours, your tank will be free of these aquarium pests. You can then turn the heat back down, vacuum your gravel and perform a 50% water change to clear the tank. Once the water temperature is back to normal, you can re-introduce your fish safely.

Planaria are often much more difficult to contain. They will generally have to be physically removed or starved through decreased feeding. These worms can regenerate when physically damaged, making them particularly problematic in large numbers. Many aquarists find that chemical solutions are the only effective solution when dealing with a planaria infestation. However, some gouramis, guppies betta, mollies and kribensis sometimes eat them.

Controlling your plants’ growth

When it comes to controlling the growth of plants in your tank, you will need to take a more careful approach since these are organisms you want in your tank, but at levels and sizes that your aquarium can support. Plants can be particularly troublesome since an improperly trimmed stem will simply grow back, often bigger than before.

The key to proper plant control is to use specialized aquascaping tools to trim your plants. Aquascaping scissors allow you to use the correct technique when trimming your plants: cut stems should be sliced at a diagonal angle that prevents the plant from simply regenerating the stem. This is very difficult to do with regular scissors, but very easy with a pair designed specifically for aquascaping.

Fish parasites and diseases

Many of the more common aquarium pests take the form of fish parasites that infect your fish and make them sick. These can seriously affect the health of your fish and often need to be addressed using a separate quarantine tank in order to separate the infected fish from the rest of your tank. Common fish parasites include:

  • Ick(ich) – This is a very common problem for fish that are stressed as a result of rapid changes in water quality or temperature. Ick infections make your fish look like it has tiny white grains of sand covering its body. Commercial cures are available in tablet form or liquid form. However, they don’t always work because some strains of ick have become immune. Raising the temperature for a week and dosing the tank with salt usually works.
  • Gill Flukes – These tiny flatworms infect the gills of your fish, and can be identified with symptoms similar to ick but with erratic movement and eye spots on the scales. Flukes cannot be seen with the naked eye. Often encouraged by poor water quality or overcrowded tanks, gill flukes must be treated immediately with anti-parasitic aquarium tablets.
  • Water Lice – If your fish seem to have pale, tiny eight-legged crabs on their bodies, you are looking at fish lice. These aquarium pests need to be physically removed from the fish and the wound treated with an antiseptic such as iodine. Another common solution is bathing freshwater fish in a salt bath of 35 ppt seawater for 5 minutes every day until the parasite falls off.
  • Gill Mites – These microscopic creatures can be identified if your fish is gasping at the water’s surface and has partially opened gill covers showing inflammation or infection. They must be treated with anti-parasitic treatments in tablet form, with water changes in between each treatment.

Hopefully, you will never have to deal with any of these aquarium pests or fish parasites. But, you should always be prepared to put a plan into action as soon as any of these pests are first spotted, before they cause problems to your plants or fish.

Once a problem has been cured, that is not the end of the matter. It is vital that you correct the conditions that caused the problem in the first place. Overfeeding, poor water quality, lighting problems, overcrowding are conditions that must be recognised and corrected so that the problems do not re-occur.