I would think the amphipods would be fine in a tank with a HOB, although you could always switch to a sponge filter, too.
As far as introducing them to a tank with fish, it would be a good idea to have a main breeding colony (aka 5g tank) in case the fish do eat all the ones introduced into their tank.
Haven't personally kept them myself, but I have seen them inside of planted tanks.
As far as introducing them to a tank with fish, it would be a good idea to have a main breeding colony (aka 5g tank) in case the fish do eat all the ones introduced into their tank.
Haven't personally kept them myself, but I have seen them inside of planted tanks.