The Fish Store

Aquarium Maintenance

Here’s where you’ll find out about how to keep your aquarium running properly and your livestock healthy.


There are many factors that will determine how frequently you feed and how much food you will need to give at each feeding, but here are a few good rules of thumb:  Most fishes really don’t need to be fed more than once a day.  In fact, many can handle being fed less frequently than that.  Large predatory fishes that are past their quick growth stage can stand to be fed a large meal 1-3 times a week.  Newly hatched fry or younger fishes in their rapid growth stage may require smaller more frequent feedings of 2-3 times a day.  Fishes that are being conditioned for breeding will also need more food.  Algae eaters usually only need some supplementation once or twice a week if there is not much algae growth for them to eat.  Most nocturnal animals can be trained to come out for food while the lights are still on.  Most invertebrates do not need as much food as the fishes because they are not expending as much energy.  Sessile (stationary) animals only need to be fed once every week or two while mobile invertebrates can be fed more frequently than that. 

Most fishes have a stomach that is an equivalent size to their own eye, so they really need less food than you would think.  Fishes behave very similarly to dogs when it comes to feeding, meaning that they will beg for food even though they don’t actually need to have the food.  They are genetically programmed to eat whenever possible because they do not know when they will find their next meal and a capable of consuming far more food at one time than they actually need.  Be strong and do not give in to the begging.  Remember that overfeeding, especially on a chronic basis, can lead to poor water quality which requires more frequent water changes to correct.

Generally, the less frequently you feed and smaller volume you provide with each feeding, the more efficiently an animal’s digestive system will work, up to a point.  Yes it is possible to starve an animal, but overfeeding is a far more common problem in an aquarium.

As far as plants go, unless you are using intense lighting and CO2 injection, you can get away with fertilizing at about ¼ of the dose recommended by the manufacturer to avoid potential algae blooms.

Scraping algae

This should be done whenever you are having trouble seeing the inside of your tank.  Some systems may need more frequent scraping than others, but regardless of how frequently you scrape, it’s usually a good idea to scrape algae immediately before changing water or while the tank is draining to prevent the loose algae from just resettling somewhere else in the tank. 

Most people will concentrate on the panels they can see through (the front and maybe one or two sides) and leave the rest for decoration or the algae eaters.  It comes down to personal preference.  Algal growth is not going to be harmful to the animals, but it can be unsightly in excess.  With that said, excess algae growth on plants or sessile invertebrates can smother and kill them.  It’s also possible that extremely large amounts of filamentous green algae in freshwater tanks or macro-algae in a saltwater tank can become so dense that the fishes can become trapped and die.

Watch out for rapidly spreading growths that form heavy sheet over surfaces and come off easily when you swish you hand past them or touch them lightly.  This type of growth is not actually an alga but a bacterium known as cyanobacteria (sometimes falsely called blue-green algae).  It can appear dark green in freshwater and reddish purple in saltwater, but other colors are possible.  The best way to treat a cyanobacteria outbreak is to remove as much as possible during a water change, treat the tank with a mild antibiotic like erythromycin for at least two days, and then do another water change.  In a reef tank, you may want to try a different product designed to work specifically in a reef tank since erythromycin can be harmful to some invertebrates.

Water Changes

Water changes should be done anytime there is a problem with water quality.  You should never have to do any more than a 50% change at one time and you can change water on consecutive days if necessary.  Any time you do a water change you always want to keep the temperature and salt content of the new water as close to those of the existing water as possible. 

If it has been a very long time since you have changed water and the chemical and physical parameters are very bad, you may need to start with smaller (10-25%) water changes and work up to 50% changes over several consecutive days.

Trimming Plants

Trim your plants anytime you no longer like the length, the plants are shading or crowding each other out, you don’t like the look of the dead leaves, or you just can’t see your animals any more.  This also goes for macroalgae and many different types of corals in a saltwater tank.

Any time you are trimming you plants try to carefully use the sharpest scissors you can to avoid unnecessary damage.

Keep in mind that cuttings from stem plants can be replanted and plantlets can be removed and replanted.   Also, we are sometimes looking to buy stuff from customers, so call us first and see if we are interested in what you may have.

Basic disease diagnosis and treatment

Disease diagnosis and treatment is a very tough subject to cover with any meaningful accuracy here.  There are a number of very good (and often expensive) books on the market dealing with fish diseases, but virtually nothing is available about invertebrate diseases.  If you suspect you are having a health issue with your fish, the best thing to do is to bring us the fish in question and a separate sample of water; about one cup.  The next best thing is to bring us a few good photographs or video clips on a camera of the fish in question and a separate water sample.  The least useful thing to do is just call and say, “My fish is sick.”

We will do our best to diagnose the problem and recommend a treatment, but many diseases require the examination of body parts under a microscope and we do not have the facilities to do that.  Also, there is a tremendous amount of training that goes into being a full-fledged fish pathologist, which most of us do not have.  On top of this, there are many medications that are very effective in specific situations that we are not allowed to sell to the public, either because they are not repackaged for resale or they are just too expensive for us to carry.

If you are having a problem with a very expensive animal or one that you are very attached to and we cannot help you, then we would highly recommend that you try to find a veterinarian capable of working with fishes.

Keep in mind that, from a strictly economic point of view, some treatments are going to be more expensive than just replacing the animal.  If you are ever in a position where you are considering simply euthanizing a fish, the easiest thing for most people to do is place them in a sealed container with a small amount of water and place that container in the freezer.  The fish’s metabolic rate is directly linked to the temperature of the surrounding environment, so the colder it gets, the more it slows down. The animal stays calm in the dark as it essentially goes to sleep and does not wake up.  Once the fish is dead it can be disposed of by whatever method you prefer.  Try to avoid opening the freezer door before the fish is dead because the sudden change in light will startle it and cause it to thrash around unnecessarily.