These little fish are really worthwhile owning for both interest and beauty. They are usually easy to obtain and don’t cost a king’s ransom.
Firefish are also commonly called fire gobies. The proper name for them is Nemateleotris xxxx. The reason I have shown the second part as x’s is because there is more than one type (this method is not common practice!). Probably the best known is Nemateleotris magnifica. The link shows photos of this fish:
As said there is more than one type in this group, two more lovely types are Nemateleotris decora and Nemateleotris helfrichi.
The fish could grow to around 3 1/8 inches (circa 8cm). They stand out not only because of beauty but because they have a very long dorsal fin, or the front part of it anyway. They are a peaceful fish which should not cause difficulties with others or with reef livestock such as corals.
The downside with these fish is that they shouldn’t be kept with larger more boisterous and/or belligerent types. This means that a fish only system is usually unsuitable. If they are kept in such a way they are likely to be always nervous and not show their true colours properly. A nervous and stressed fish is more likely to succumb to disease or just fade away.
The best place for firefish to be housed is in a reef system. The fish need a cave that is deep inside the reef for security, which they can dive into if danger seems near. This is the problem with incorrect tank mates; the firefish could be mostly afraid to leave their cave and even if they do it will not be for any distance. In the reef system they should be kept with small quiet non-aggressive fish. As said there isn’t any danger to corals.
Stocking is straightforward with simple guidelines. The firefish should be one of the first fish into the aquarium so that it can settle before other fish arrive. They will select a cave deep in the reef and gain confidence. One firefish could be introduced, but in the wild they tend to live in pairs* so two could be introduced at the same time. More than two pairs could be introduced provided the aquarium is large (the minimum suggested size for a pair is 30 inches (circa 76cm). This way the flicking of the dorsal fin will probably be seen, this is thought to be a signaling device. It might be thought that the higher seawater circulation in a reef system would be a problem for the fish, but usually it isn’t, the recommended flow is medium to strong. Though it doesn’t usually cause a serious problem, strong lighting is not particularly liked; the preference of the firefish is for moderate intensity. However, if the firefish is unhappy it could select an area where the lighting is not so strong, these usually are present in most reef systems.
Feeding is not a problem normally. In nature the fish take food from the seawater column, mainly plankton. Of course this is not possible in an aquarium situation. However, if suitably sized food is floating in the current the fish will normally go for it. Marine flake, brine and mysis shrimp are suitable, plus any other foods that are similar. If live foods are available such as brine shrimp these will usually also be taken.
When the aquarist first introduces the firefish to the aquarium they are likely to dive into the rocks and disappear. However, after a time, maybe a day or so, they should re-appear and start to hover in the seawater column. At this early stage they will probably dive back into the rocks when the aquarist approaches. However, as time continues this should reduce and the fish could even commence to ‘beg’ for food as do many other species. The normal daytime practice is for the firefish to hang in the seawater column above the home cave location waiting for food to pass by.
The firefish is reported to be a ’jumper’, that is, it has been known to jump out of the aquarium. Why this should be is not certain, maybe more boisterous fish spooked them. When I kept firefish they never jumped at all – their companions were peaceable and small so perhaps that was the reason.
In a suitable environment firefish should not present any problems. They are usually easy to feed and provide, in addition to their beauty, a slightly different looking fish.
(*Reference: Marine Atlas. Helmut Debelius & Hans A. Baensch)