Fish That Start With X
Browse all aquarium fish species with common names beginning with "X". Each profile includes care requirements, water parameters, tank size recommendations, and compatibility information for freshwater, marine, and brackish species.
The letter 'X' features a handful of intriguing species that can enhance any freshwater aquarium. The vibrant Green Swordtail (Xiphophorus hellerii) is a notable entry, alongside the lesser-known San Marcos redtail splitfin (Xenotoca doadrioi). These species are popular among hobbyists for their unique colors and compatibility in community tanks.
Xenochromis hecqui (often listed without a stable aquarium common name; avoid confusing with Hecq's shell-dweller)
Xenochromis hecqui
Xenochromis hecqui is a Lake Tanganyika cichlid associated with deep-water habitats (reported captures to ~100 m). It is a specialized scale-eater (historically placed in Perissodus as P. hecqui).
Xingu spotted catfish
Zungaropsis multimaculatus
This is a super obscure pimelodid catfish from Brazil's Rio Xingu, and it is basically a mystery fish in the hobby - you almost never see real, confirmed aquarium care info for it. Taxonomy-wise it is even considered "uncertain" and has been suggested as a possible synonym of the much larger jau catfish (Zungaro zungaro), so I would treat anything sold under this name with extra caution and verify the ID hard before you plan a tank around it.
Xingyun Lake Yunnan loach
Yunnanilus analis
Yunnanilus analis is a little bottom-hugging stone loach from China, originally described from Xingyun Lake in Yunnan. Its species name is literally about the anal fin - it has six branched anal-fin rays, which is a weirdly specific ID feature. This one is not an aquarium regular, so if you ever actually see true Y. analis for sale, it would be a pretty unusual find.
Xiuren torrent catfish
Xiurenbagrus xiurenensis
This is a tiny little Chinese torrent catfish from the Pearl River drainage - think bottom-hugging, hidey fish that wants clean, oxygen-rich water. It stays around 10 cm/4 inches and is more of a nighttime rock-and-crevice cruiser than a "front glass" pet. If you set it up like a cool, fast stream with lots of cover, it should act way more confident.
Xixi high-plateau loach
Triplophysa xiqiensis
Triplophysa xiqiensis is a little Chinese stone loach from cool, flowing hill-stream type water, and it lives right on the bottom picking around the substrate. It is the kind of fish that spends its day cruising and perching on rocks, so it is way more about behavior and habitat vibes than flashy color.
X-ray tetra
Pristella maxillaris
This is that little see-through tetra where you can kinda make out the spine inside the body, and then it tops it off with those sharp black/yellow/white fin markings and a reddish tail. Super chill schooling fish, and it's one of those rare tetras that doesn't freak out if your water isn't "perfect Amazon blackwater" 24/7.