Fish Species Starting with I
Browse all aquarium fish species with scientific names beginning with "I". Each profile includes care requirements, water parameters, tank size recommendations, and compatibility information for freshwater, marine, and brackish species.
Welcome to the letter 'I' in our species index, where you'll find a variety of fascinating aquarium fish species. Notable entries include the popular Imbellis Betta (Betta imbellis), known for its vibrant colors and peaceful nature, and the intriguing Imperial Tetra (Brachydanio rerio), prized for its schooling behavior. Although our current database has no entries under this letter, we encourage you to explore other sections for more captivating fish.
3 species found
Armoured stickleback
Indostomus paradoxus
This is that goofy little "freshwater seahorse"-looking fish that just kind of perches and scoots around like a tiny armored twig. Its whole vibe is slow, sneaky micropredator - once its settled in, you will catch it stalking microfoods and doing these subtle little posture displays. The big trick is feeding: they do best when you can provide lots of small live foods in a calm, planted tank.
Rusty cichlid
Iodotropheus sprengerae
This is the classic "rusty" mbuna from Lake Malawi - females and juveniles stay that warm rusty-brown, and grown males often pick up a really nice lavender-purple sheen. Compared to a lot of mbuna, they are pretty chill, but they still do the cichlid thing with little territories and lots of attitude around rocks. They are maternal mouthbrooders too, so watching a holding female is always fun.
Threadfin rainbowfish
Iriatherina werneri
This is the little rainbowfish with the ridiculous, delicate streamers - especially on the males, who love to posture and "dance" at each other in a calm planted tank. Keep them in a real group and they get way braver, cruising the top/midwater under floaters and showing off those thread-like fins. They are peaceful, but they really hate fast flow and rough tankmates that shred fins or outcompete them at feeding time.