Aquarium Husbandry

How to Keep Fish Tank/Glass Clean

A properly maintained aquarium is essential for the long-term survival of fish and invertebrates.

The best way to keep an aquarium clean is to have all the proper equipment and use it. It is also a mater of know how. There are a few things that every aquarium owner must understand in order to be able to maintain it in the best possible way.

All aquariums work on a finely balanced bacterial system and over-cleaning may actually be detrimental. Various bacteria grow in the filtration system and in the gravel. Bacteria known as nitrosomonas consumes harmful fish waste in the form of ammonia (NH3) and break it down into nitrite (N02). A second bacteria known as nitrobactor then consumes this nitrite (N02) and converts this into the less harmful nitrate (N03). This is known as nitrification or the nitrogen cycle. Nitrate in freshwater aquariums will be utilised by aquarium plants and also diluted through water changes.

In saltwater aquariums nitrate (N03) may be detrimental to certain corals and invertebrates and therefore greater care in its removal is required. Water changes will dilute it to some degree, however there are many ways to remove this naturally in the aquarium. Keeping caulerpa a type of marine algae, will in the same way as a plant use nitrate as a food source. The drawback of using this in the main aquarium is that it can quickly grow and overtake your aquarium. This is why sumps are often used, a method we will come to later. Secondly there is a type of naturally occurring anaerobic bacteria that consumes nitrate as a food source. In marine reef aquariums ‘live rock’ is generally added, inexperienced aquarists may think that this is purely for decoration and may skimp on this, instead purchasing plastic or dry rock. Live rock however is fundamentally the most important introduction for a marine aquarium. Firstly live rock will add an unbelievably large array of organisms to the aquarium, most of which are extremely beneficial. Among these organisms are bacteria as mentioned above, which in turn will filter your aquarium as it has done on the reefs for millions of years. There are many various ‘gadgets’ now that are based on the anaerobic method that is carried out inside the liverock such as sulphur de-nitraters or marine bio pearls. All of which are designed to increase the overall amount of anaerobic bacteria in the system.

Cleaning your aquarium so that these bacteria are not disturbed can be difficult. A common mistake is for novices to clean the filter sponge under the tap in order to ‘clean’ it. Tap water contains amongst other things chlorine and chloramines which are specifically designed to denature bacteria, whilst great for drinking, tap water will kill off any ‘good’ bacteria’s found on your sponge. If no bacteria is present in the filter whilst you have fish in the aquarium ‘new tank syndrome’ may be a side affect. The fish will still continue to produce ammonia and if there are no biological sources to remove this, ammonia levels will rise and will kill your fish. The first signs of this are fish gasping at the surface then usually a cloudiness of the water. So we now know it is important not to clean the filter under the tap, but we still need to clean it so what do we do? Well from personal experience the best way to clean a biological filter is to squeeze it out in aquarium water that has been removed from the main aquarium during the water change. This will allow the mechanical removal of ‘sludge’ whilst still retaining the bacterial colonies. The filter sponge can then be reinstalled back into the main filter unit and switched back on.

Every aquarium is different, so there is no fixed rule for cleaning. However it is generally advised to remove up to 25% of the aquarium water per week and replace it with fresh de-chlorinated water for freshwater aquariums, or salted Reverse Osmosis (R.O) water in marine aquariums. The best way to do this is with a syphon-based gravel cleaner that will clean the aquarium substrate in the aquarium at the same time as removing the water. This will also aid in keeping bacteria in the substrate rather than removing it and risk loosing the beneficial balance.

Aquarium Husbandry
Aquarium Husbandry

Cleaning the glass prevents algae from building up inside. If the aquarium is made from acrylic then cleaning the acrylic panels should be performed more often, perhaps once a day with a specific acrylic scraper or cleaning pad. When performing maintenance operations to your aquarium, you should always keep in mind a few things to ensure that things are going smoothly inside your aquarium. It is imperative that there is enough oxygen for the fish but also to allow for proper flow of the water so daily checking of equipment is imperative.

Weekly water testing is advised, this is so you can monitor your aquarium levels and balance, and will also be a good indication of water quality. Before fish can be introduced into a new aquarium, nitrite and ammonia should be zero and in freshwater Nitrates below 20ppm (parts per million). In saltwater nitrate is recommended to be undetectable as well as zero nitrite and ammonia. pH (a measure of acidity and base in a aqueous solution) is another important test, however this level will vary dependent on the type of system; i.e Reef aquariums are generally best kept between a pH of 8.2 – 8.4 whereas freshwater community aquariums will be kept around the pH of 7.0, although some species of fish prefer it more acidic such as common tetras while others prefer more alkaline conditions such as Malawi cichlids. Therefore it is important to consider what fish you will be keeping in your aquarium to enable the correct levels for good health.

It is advisable to keep a schedule for maintenance operations and testing so that should any problems arise you will have detailed accounts that could be passed on to your LFS (local fish shop).