Aquarium Professionals Group Article 
Answers to Common Questions:

  We Have the Answers
In our twenty five years in the aquarium business, we have received many calls from clients with questions about their aquariums. Many of these questions were for basic information that doesnít fit any one particular category. Weíve also gotten a lot of questions regarding odd fish behavior and strange aquarium phenomena. Weíve assembled a list of the answers to many frequently asked questions about fish and aquariums in general.

   Do Fish Sleep?
Fish do sleep. Most fish donít have "eyelids". If the aquarium lights are left on for twenty-four hours a day, the fish will not sleep. They will become stressed, and eventually theyíll die. Most fish sleep lying on the bottom of the tank. If the room is dark, and youíve just turned your aquarium lights on, donít worry, your fish arenít dead, theyíre sleeping!

  Do Clownfish "Need" an Anemone?
Clownfish (saltwater) are unique in that they form one half of a symbiotic (mutually advantageous) relationship with anemones (a flower-like invertebrate related to corals). Anemones are predatory. If a fish or free-swimming invertebrate accidentally strays into the tentacles of the anemone, the anemone stings the prey and eats it. Only clownfish (and several species of damsels as well as some specialized crustaceans) are immune to the anemoneís sting. The clownfish lives in the deadly tentacles of the anemone, receiving protection from predators and shelter. In return, the clownfish will often "feed" the anemone, stuffing food into its mouth. Not all clownfish in the ocean have "host" anemones. 

A clownfish kept in an aquarium without an anemone does not suffer. In the absence of an anemone, they may exhibit unusual behaviors. The clownfish may sleep at the surface of the tank on its side. It may even live at the surface of the aquarium. It may also adopt a shell or hollowed out piece of coral as a "pseudo-anemone", and will stay near or in this adopted "host".

  One of My Fish Changed Color in an Instant - Why?
Fish have wonderful cells in their skin called melanophores. These enable almost all fish to change their coloration and markings at will. Some species can change their coloration and marking pattern in less than one-tenth of a second! Fish may change their color when theyíre sleeping, stressed, attracting a mate, defending a territory, or eating. Some fish have several coloration schemes for different functions, such as camouflage. 

If a fish in your aquarium has changed its color or markings, thereís nothing to be worried about, unless the fish maintains the different coloration for more than a day. This may indicate major stress, and you should call us. If ALL the fish in the aquarium have changed color, this usually indicates an urgent emergency situation!

Red streaks that appear on the body and in the fins in some of the fish in a tank are not caused by the fish changing color. This may indicate a low dissolved oxygen situation and immediate steps must be taken to correct it. Yellow Tangs in saltwater, and loaches, catfish and goldfish in freshwater will usually exhibit this symptom first.

  Do Fish Drink?
Saltwater fish drink water and obtain many required trace nutrients from the water they drink. Freshwater fish do not drink water, and obtain nearly all of their nutrients from their food.

  My Blue Tang is Laying on the Bottom of the Tank - Is it Sick?
Blue Tangs (also called Blue Surgeonfish) when stressed or scared, lie on the bottom of the aquarium on their sides until they sense that all danger has passed. If your Blue Tang is lying on the bottom of the tank, and its gills are still moving, it isnít dead. Itís playing dead!

  Also of Note:
Both saltwater and brackish water Puffers lay on the bottom of the tank periodically, especially after eating.

Lionfish (saltwater) do not swim much. They can usually be found in their rather unusual resting position. They lay head down, with their belly against a piece of coral, looking cool and waiting for prey to come along so they can pounce! Of course, in an aquarium, the prey (hopefully) never shows up, but the Lionfish never gives up waiting.

   Why Did My Hermit Crab Die?
It probably isn't dead at all! ermit Crabs and all other crustaceans molt in order to grow. They have a hard shell (exoskeleton), and they cannot grow inside it. They first shed their old exoskeleton. Then they grow by swelling up their soft-shelled body. The actual growth only takes a few minutes! While they remain swollen, their new exoskeleton hardens, and the process is finished. The old exoskeleton they leave behind looks like an exact replica of the original animal! If you have a hermit crab or other crustacean, and one day you see it looking "dead" at the bottom of the tank, look closely! Itís only a "molt". 

To make matters worse, the crustacean preparing to molt will often hide and stop eating for a few days before and after molting. That hermit crab shell that hasnít moved for a week still has a crab inside it. Donít throw it away!

   My Aquarium is Cloudy - What's Wrong?
If the aquarium water turns cloudy almost overnight, always check to see if all the filters are running before calling us. A white cloudy, swirling condition (looks like someone poured a little milk in the tank) may indicate ammonia. If all the filters are running, count your fish, and check their condition. If a fish dies and goes unnoticed, the tank may develop this white cloudy condition. If the tank exhibits a yellow, gray, or green cloudy condition, and the fish are all eating and appear healthy, this is a bacterial or algal "bloom". Although unsightly, this is not a dangerous condition. 

Bacterial or algae blooms are usually due to any rapid fluctuation in environmental conditions, such as a heavy over-feeding (usually by someone caring for your fish while youíre on vacation), high temperatures, or a build-up of detritus (fish waste and uneaten food). The cloudiness is caused by billions of free-floating bacteria (yellow or gray) or algae (green) that have populated the water by rapid division. We can correct this problem by doing a series of water changes and/or putting a special temporary filter (diatom filter) on your aquarium for a few days.

   Why is One of My Fish Displaying Odd Behavior?
Fish occasionally exhibit "odd" behavior. A fish that is quivering, fluttering its fins, or shaking in front of another fish, is probably exhibiting a breeding or defense behavior. Watch and see if the fish does this when another fish approaches it. Some fish gape at another fish with a wide open mouth, which is a defensive behavior. Fish that lay on their sides when another fish approaches are displaying "submission" to another, stronger tank mate. Another submissive posture is exhibited by some species by remaining motionless in a head-up position for a few seconds. Saltwater angelfish often swim on their sides. Some species of African Synodontis catfish, saltwater butterfly fish, and lionfish will occasionally swim upside down!

Fish do yawn! An occasional yawn is normal! If all the fish in an aquarium are yawning every few minutes or so, call us. This may indicate a dissolved oxygen or temperature problem.

Some wrasse and parrotfish species (saltwater) will scratch or bang their heads against a piece of coral occasionally. If it only happens occasionally, this is normal. They are only knocking loose a clot of salt from specialized salt excretion glands in their gills. If fish other than these species are scratching, or the scratching is happening frequently, you should examine all the fish closely then call us. This may indicate the beginning of a parasite problem or a low pH condition in the water.

Some fish dig pits in the gravel. They are simply building a home as they would in the wild. If this should ruin the aesthetic beauty of the aquarium, there is little you can do about it, short of removing that fish. Fish that dig pits include: in freshwater, many types of Cichlids, Catfish and Eels; and in saltwater, certain species of Gobies, Triggers, Parrotfish, Wrasses, and Eels as well as certain crabs, lobsters and shrimp.

Some saltwater fish may occasionally gnaw on the coral decorations. They include Parrotfish and some Triggers. Parrotfish eat coral in the wild. Triggers eat anything, and they may also be sharpening their teeth.

   Can a Sick Fish Introduce Disease to My Aquarium?
It is technically not true that introducing a sick fish into a healthy aquarium introduces disease that can harm the rest of the fish. However, there is no question that introducing a sick fish into a tank will almost always cause problems. 

Environmental stress is what allows a fish to be attacked by diseases. Causes of environmental stress are: water changes, rapid fluctuations in temperature, the decay of a dead fish or a lot of uneaten food left in the tank, or a filter thatís stopped working. 

When a new fish is introduced into a tank, this too may be a cause of stress. Territories change. The pecking order changes. If the new fish was carrying a disease, and the other fish are stressed by its introduction, then they might fall prey to the same affliction. 

Parasites and other harmful microorganisms are always in every aquarium. Luckily, a fish has a wonderful immune system. The primary barrier to diseases is a protein-based slime coat that covers the body of the fish. When a fish becomes stressed, they may stop excreting this slime coating. They then become targets for harmful microorganisms that are constantly trying to penetrate this invisible barrier. The use of an ultraviolet sterilizer lessens the risk of disease by destroying many of these free-swimming microorganisms in the water, and is highly recommended, especially for saltwater aquariums.

  My Fish Have White Spots - Are They Sick?
The most common disease that occurs in aquariums takes the form of tiny white cysts on the body and fins of the fish. They look like tiny grains of salt. Symptoms include rapid gill movement and scratching against objects. This is caused by a one-celled parasite. The tiny white grains of salt are actually calcium cysts secreted by the parasites to protect them while they feed. 

Identical symptoms, and the form this disease takes, occur in both freshwater and marine aquariums, although it is a different animal that causes the problem. In freshwater the parasite is named Ichthyophthirius multifiliis, which we call "Ich" for short. In saltwater the parasite is named Cryptocaryon irritans, which we call "Crypt" for short. Both feed on the bodily fluids of fish. Both have a ten to fourteen day life cycle. Fortunately, if the problem is caught in time, both diseases can easily be cured. It is a good idea to look closely at your fish at least once a week for signs of trouble and call us right away if you see this problem.

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