Eel – Moray 450mm

Freshwater (brackish) Moray Eel (Gymnothorax tile) also known as Indian mud moray and snowflake eel.  Their fierce look, their snakelike elongated body and their general oddball attitude lure many fish keepers into buying them. But freshwater moray eels are not really what their common name pretends they are. These are not recommended for the standard community tank as they sometimes start to eat their neighbors. Under the right conditions and with appropriate care they can be wonderful fish living for more than ten years.

Moray eels need brackish or marine water to thrive. They can last in freshwater for months or sometime years, but that is far away from the optimal care and thus should be avoided. In nature they do not stay in freshwater. They make trips up freshwater rivers for food, maybe to get rid of salt water parasites, possibly even for spawning, but they return to higher salinities within weeks.  Their natural habitats are the tropical estuaries and coastal mangrove swamps. Salinity in these areas changes with the tides and the monsoon, but mostly is rather close to marine. That is why a specific gravity of at least 1.010 is needed to keep a freshwater moray eel healthy. A full marine environment may be even better (especially for the adults) and is, due to the use of live rock and skimmers, easier to maintain.

Behavior

Besides their mostly nocturnal exploring trips, freshwater morays are rather inactive fish even compared to other species of moray eels. They will sit in some cave, preferably a narrow gap, all day and watch curiously what is happening around. They will only leave their cave if they smell food, see something very interesting or if the lights are turned off. But even then, there is not much activity, five or six rounds in the tank, a look in every corner and that’s it. Consequently it is important to offer them lots of narrow caves and holes.

Tank Conditions

Moray eels may be predators and they may seem to have a vicious look in their eyes, but be aware that they are very easily stressed. Moving decoration around, netting the fish and especially changing the tank all can result in a scared moray eel that won’t eat for days or even weeks. So its good to reduce such actions to a minimum.

Morays are very curious at night and investigate every crack or gap for food or eventual hiding spots. Keeping a moray eel in a tank without a tight fitting lid is a bad idea. It is important to tightly seal all holes in the lid, because they not only like to investigate holes, but wiggle their way through them ending up on the floor. It is frequently reported they ended up dead on the floor. If it manages to escape and looks dead, get a net as soon as possible and put it back in some saltwater. They are hardy and even after hours there is a chance for survival.

It is important to offer them lots of narrow caves and holes. Plenty of reef rock seem to be the perfect choice. If you are using a marine tank, porous live rock would be even better. As substrate avoid sharp things like broken oyster shells and prefer aragonite sand.

Because they don’t swim that much, it may seem, that they need only small tanks, but actually that cannot be recommended. Due to their predatory diet, they produce a lot of waste which quickly can raise nitrate levels in a small tank. A relatively large volume of water and adequate filtration in addition to regular water changes are needed to keep the good water quality needed for long term success. Tank size for one adult specimen of Gymnothorax tile should be at least 120 litres, two should consequently have 240 litres. As with all fish, more would be even better.  Some even recommend a minimum tank size of 500 litres.

Compatibility

It’s a bit tricky to find good tank mates to morays, since they eat anything small enough, are easily stressed and therefore can’t be kept with too aggressive species and are brackish water species which further narrows the field of potential companions.  you to keep more then one moray in your aquarium. They are not aggressive towards each other and often share caves which give a nice touch to the aquarium. However you might still want to have some other species in the aquarium such as bigger dats (trigger fish) who usually don’t hassle morays and maybe scats, monos, or puffers (brackish).

Feeding

Many first time moray keepers have problems to get their freshly bought moray eel to eat. Morays are robust and can live for at least one month without food, but given they already spent some weeks in quarantine and the fish store without being appropriately fed, they may starve quite soon after being bought. If the tank and water are properly setup then you shouldn’t have problem feeding them, they will accept most kind of live and frozen food.

A good diet seems to consist of a variety of live fish/crustaceans and frozen seafood.  They usually don’t accept pellets. A varied diet is as always preferably, such as frozen shrimp (the kind you buy in your grocery store) and frozen fish that isn’t to fat. Once in a while give them live fish. Don’t be surprised if the fish survives a few days, sooner or later it will become food. Tyr varying the diet a little with different lower fat meats, crayfish etc, just use your imagination.

Hand feeding is possible and recommended, but may be a bad idea without using long tweezers. The mucous membrane of the mouth produces a weak toxin and their bites will draw blood and can be painful.

Care

Although this fish is very hardy in brackish and marine water, they are prone to a number of diseases in freshwater. If the conditions are not right, they will reject food and starve to death, although in freshwater they can manage to decimate their community tank mates before being weakened from various infections and parasites.

Click for Fish Disease Diagnosis and Treatment at Rebel Pets.