from what i understand most rays are wild caught. also i know most piranhas that are wild caught will have tapeworms so im guessing its a good possiblility rays might also considering they are all coming out of the same amazon water as piranhas are
put them in a quarentine tank and treat them in there.......... or else put them in your main tank and treat it instead. using a smaller quarentine tank would mean a smaller dose because less water.
mine seem to be fine but i didnt notice any tapeworms on the bottem in my sand
IMO fish look better when they are darker and not as pale but thats just my opinion. In my mind I just assosiate pale fish with less healthy stressed fish.
males has 2 pointy things called claspers like in this pic. the females dont have these. its quite easy to tell actually. this sample pic is of a male retic with a 4-5 inch disc