Threadfin Cardinalfish - Medium

Threadfin Cardinalfish

The Threadfin Cardinal is a hardy fish and so is a great choice for a beginner. They are very peaceful and social fish and so it is actually recommended that they be kept in a peaceful reef tank in a group of 5 or more other Threadfin Cardinalfish.

These fish are only small growing up to a size of around 6.5 cm.

These Cardinalfish are both reef safe and coral safe and won’t harass any snails, Starfish, or crabs in the tank. inverts present in the tank. They are slower swimmers which makes them slower eaters as well and it’s not good to keep them with fish that will outcompete them for food.

These fish originate from the Red Sea around Mozambique Island right over to the east around Samoa and Tonga, then north up to the Ryukyu Islands and south to New Caledonia and Micronesia. They are usually found in sheltered bays and lagoons in the wild.

Tank Recommendations for Threadfin Cardinalfish
If you are keeping one of these on its own then a 38-litre tank would be large enough. As these fish are usually kept in a group of 5 or more then we’d recommend keeping them in at least a 114-litre tank.

The Threadfin Cardinalfish is reef and coral safe and will appreciate some branchy stoney corals to linger around.

Suitable Tank Buddies
The Threadfin Cardinalfish is a very peaceful species and so should be kept with other passive fish. The usual advice as with all small fish is don’t house them with any larger predatory fish that can fit them in their mouths as they’re likely to become lunch.

Usually Compatible
As these fish aren’t aggressive and are also slow swimmers it does make them some of the few fish that are compatible to keep as tank mates with Pipefish and Seahorses. You can also keep them with Blennys, Gobies, Dragonettes, Filefish, Clownfish, Boxfish, Butterflyfish, and Dwarf Angelfish without issues.

Sometime Compatible
Large Angelfish, Hogfish, Rays, Tangs, Damsels, Wrasses, and Pufferfish can sometimes be problematic. When kept with these the Cardinalfish can struggle to eat by the more aggressive fish. Incompatible Tank Buddies Tanks mates that you can’t keep with your Threadfin Cardinals are the usual suspects that would be very likely to eat them and those are Groupers, Sharks, Scorpionfish, Lionfish, Eels, and Snappers.

Feeding Your Threadfin Cardinalfish
These fish are carnivores and so their diet should include a variety of live or frozen mysis or brine shrimp and feeding should occur 2-3 times a day.

You can also feed them chopped crustaceans and shredded fish. They will also happily take live copepods, they will also take small pellet foods.