Catfish Compatibility

[C_H_R_I_S]

Hi, I have what I think are a Cuckoo catfish and featherfin catfish. They get on very well and are always swimming around together, would they be compatible with shark catfish that are the same size? Thanks

 

[MartinS]

If you mean Ariopsis seemani (previously known as Arius seemani), then although they will probably 'get on' they get too large for the standard tropical tank (in excess of 14" TL) and have very different water requirements. If you are keeping genuine cuckoos (Synodontis mulitpunctata), these do better in hard, alkaline water with rift lake cichlids, whereas the featherfin (Synodontis euptera) is an larger, more active riverine syno that will be better in a community of larger fish, such as barbs.
As attractive as the shark cats are, I'd avoid them. Another fish that is not really suited to aquarium life.
IMO I'd have a think about what your future plans are and either keep the cuckoos, or the featherfin, but not both - uness you have the space to set up tanks for both species.
Martin