Hiya
What type of water conditioner have you been using also how ofter were you changing 1/3 of the water* lastly were you hoovering the gravel as the gravel filter is not efficient by itself
75f if fine but better 71/73f
There is a product called lymnozyme helps fight bad bacteria and breeders swear by it* but requires very careful drops,bloat usually begins with poor water condition followed by bad bacteria* lymnozyme competes with the bad bacteria
http://www.xenopus.com/products.htm scroll down btm