The Prettiest Cardinal You Forgot About

Posted by Quality Marine Staff on January 24, 2023

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The Yellow Striped Cardinalfish also known as the Orange Lined Cardinalfish (Ostorhinchus cyanosoma) can reach a max size of about three inches. Their body has neon orange stripes over a silver body which can be a bright metallic blue, especially towards the head. They have large eyes and mouth relative to their body size, helping them with feeding and seeing in the dark.

Yellow Striped Cardinals have a very wide distribution, from the Northern Pacific all the way to the Red Sea. It is possible that O. cyanosoma will be divided into more species in the future, but currently they are all one species with a very large range. This fish was collected in Tonga during a QM vendor visit and found that there they prefer to spend their time under rock or coral cover in caves. They can be found from inside coral lagoons in shallow warm water only a couple feet deep, or as deep as 50m where they live in the branches of coral. Mostly these fish are found in shallower water, and it isn’t uncommon to see large groups living within the spines of a long spined urchin.

These fish are social, and while one would most likely be fine in an aquarium a small group would be better. A pair or trio would be the minimum recommendation – and however many you choose, you will need to provide them with an adequately sized cave for all of them to fit in. They are nocturnal, so they will prefer cover in a brightly lit reef tank. Densely branching hard corals or a long spine urchin could make a unique display for a group of these fish. With a three inch maximum size, a pair could potentially be held in a ten gallon aquarium, but larger is always better. They form groups of mixed sizes and ages in the wild; mimicking this in a larger aquarium would be a very interesting way to display them.

Cardinals are not picky when it comes to food. In the wild they mostly eat plankton and other small invertebrates or scraps that drift past their home (either a cave, urchin or coral) so that they can feed without the worry of leaving cover. As a result, they will relish any variety of small meaty foods, and are easy enough to feed something as simple as a high quality flake food. It is not uncommon for them to grow so bold that they will take flakes from the aquarists fingers! High quality flakes and pellets can be supplemented with table shrimp, mysis, brine shrimp or other such foods. Their largemouth means they can take advantage of the majority of food items that drift by – so be wary when it comes to very small invertebrates or fish being held with them. If it fits in their mouth, they will try to eat it!

Yellow Striped Cardinalfish are mouthbrooders meaning that after the female releases her eggs and the male fertilizes them, he picks up and carries the eggs in his mouth until they hatch! Cardinalfish males and females are frequently similar in appearance when small, so if your intention is to breed them you should consider starting with a group of at least six to eight individuals to insure you have at least one male and female. Cardinalfish exhibit pairing, but usually only starting with courtship and ending shortly after the male has taken the egg mass into the protection of his mouth. Courtship usually starts with two fish isolating themselves from the group, then usually at dusk or dark the female will release an egg mass which the male will fertilize, and then carry in his mouth until the babies hatch. The juveniles that emerge from their fathers mouth will be miniature copies of the adults, and so long as they get adequate sized food and can avoid being eaten, they should have no issues joining the rest of the colony within your tank (this is why a bigger tank or cave might be beneficial). Yellow Striped Cardinals are being aquacultured, but not in very large quantities at the moment.

The Yellow Striped Cardinal fish is beautiful and hardy. Its social behavior and mouthbrooding of its young makes it fascinating to observe. You’ll have a hard time finding a better small cardinal fish to occupy a cave in a reef tank! Talk to your local fish store today about getting some sustainable Yellow Striped/Orange Lined Cardinalfish from Quality Marine today!