Had you done research on the species prior to purchase? That's always your best bet. You actually need to go to the lfs
prepared to argue with them about their recommendations. Sad, but true.
I would return them. I saw my husbands pleco attach itself to a sick fish but never healthy fish. Don't know about your species, but wonder if there is not a sufficient supply of algae, if they will grab the next best thing.
75: blood parrots, featherfin cat, emperor tetras, turquoise rainbowfish, BN plecos, japanese trapdoor; 46: WCMM, gold inca snails, ghost, bamboo & amano shrimp, kuhli loaches, rummynose & ember tetras, endlers, platies, flame gourami, guppies; 16: pygmy, peppered, loxozonus corys, otos, assassins, RCS ... ~ Research PRIOR to purchase.... ~