Seal the top before the fish comes home
A clown killifish escapes through openings other fish ignore, so the lid is the first part of its introduction. This species lives pressed against the surface of slow forest streams and launches itself at insects, which in a tank means launching at the gap around a filter pipe or a feeding hatch. Fit a lid with no open corners, plug cut-outs with mesh or foam, and check the seal again after every water change. Only once the top is genuinely closed does it make sense to bring the fish home, because a killifish found on the carpet is almost always a lid failure, not bad luck.
Recreate the shaded surface it hunts along
A clown killifish hunts under cover, so floating plants are furniture, not decoration. A canopy of floating leaves dims the light, gives males shaded stations to display from, and calms a fish that feels exposed in bright open water. Keep the flow gentle enough that the surface film stays mostly still, since this fish picks food from the film rather than chasing it through current. Soft, slightly acidic water suits it, and a dark substrate with leaf litter below completes a setup that reads to the killifish as the edge of a quiet stream rather than a display case.
Acclimate gently and release at the surface
A clown killifish arrives stressed and pale, and a slow acclimation restores its colour. Float the bag to match temperature, then add small amounts of tank water over half an hour or more, since the soft water it prefers often differs sharply from shop water. Net the fish out rather than tipping bag water in, and release it just under the floating plants where it naturally wants to be. Expect it to hang motionless for a while; males regain their orange tail flame and blue-grey sheen over the first day or two as they settle into their stations.
Feed at the film, in portions it can finish
A clown killifish eats what lands on the surface and little else. Its upturned mouth takes fruit flies, baby brine shrimp, small mosquito larvae and fine floating foods, while food that sinks past it is simply lost. Feed small amounts twice daily and watch each fish rise and pick, because a shy individual stationed at the far end can miss every meal in a group tank. Frozen foods thawed and placed on the film work well, but vary them with live food when you can — the hunting behaviour it triggers is half the pleasure of keeping this species.
Watch the stations, the lid and the waterline
A settled clown killifish holds a favourite spot under the plants, displays to rivals and rises quickly at feeding time. A fish pressed into a corner, gasping at the surface or faded to grey needs the water checked first — temperature, and whether a filter change has sped up the flow. Recheck the lid seal weekly, since warping and shifted covers reopen the escape routes this fish finds so reliably. If a killifish stops feeding and wastes away despite calm, matched water and live food, an aquatic vet should look at it rather than the tank being treated blindly.
Because this fish depends on habits like the lid check and surface feeding that anyone in the house might do, KinsLe Family Sharing keeps the clown killifish's routine on one shared profile the whole family reads before touching the tank.