THREADFIN RAINBOW (Iriatherina werneri)

Very peaceful but not suitable for the general community aquarium since it’s easily outcompeted for food and the long fins of mature males may be nipped at by certain common species. It’s best maintained alone or alongside fishes of comparable size and disposition such as Pseudomugil spp., or if geography isn’t an issue Microdevario, Danionella, Eirmotus, Trigonostigma, pygmy Corydoras, small loricariids such as Otocinclus spp., and freshwater shrimp of the genera Caridina and Neocaridina are also suitable.

It’s a shoaling species by nature and really should be kept in a group of at least 6 specimens, ideally 10 or more. Maintaining it in such numbers will not only make the fish less nervous but result in a more effective, natural-looking display. Males will also display their best colours and some fascinating behaviour as they compete with one other for female attention.

https://www.seriouslyfish.com/species/iriatherina-werneri/