Can I keep male Guppies without females?
Can I keep only male Guppies together with 2 - 3 Otocinclus affinis in a standard 60 cm aquarium?
this is not really optimal - besides, it is going to become difficult to actually get Otocinclus affinis: This species is almost never available in the trade; the fish sold under this name are almost always other species (it is therefore advisable to find out under which conditions the fish live in nature, as, for example, temperatures vary strongly).
Although it is possible to keep male Guppies without females due to the peacefulness of the fish: The natural behavioral pattern of the fish of course includes the possibility to reproduce, you should not withhold it from them. However, you may add predators that limit the number of baby fish.
Midget Sucker Catfish should be kept in larger groups consisting of at least 6 - 8 specimens.
Dr. Bodo Schnell