How to control aquarium pests
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 – 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 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.