I got some female betas before and they were fine together but did make the mistake of putting them in the big tanks with the big algae eater and she did eat them. It took a little while to realize we couldn't put anything below a certain size in with her. Now she gets frozen blood worms thrown in for protein and she ignores the other fish but we still don't ad anything small. They also like veggies. Throw some spinach and other things in sometimes for the algae eater. Ours even likes carrots and celery but usually takes a few days before you really see bites out of it. Well little of that is about betas but you can make algae eaters happy with treats.