Ive never heard of any mishaps with terracotta pots, seen them around quite abit in tanks. Just make sure you give them a really good washing to get all proctus tags and stickers off and to make sure theres no dust or any other harful drit or stuff on it. On another note, and a cheaper one!, you can get alot more creative using rocks that ya find outside, there free... of course they still need to be throughly washed before adding them to your aquarium, but they will give the tank a more realistic look and the cichlids will feel more at home. Good luck!