Hi! I bought a fantail goldfish a week ago from the pet store. He has everything in his tank: a lot of space (25 galons), filter, oxigen pump, gravel and a few decorations. He is quite tiny, having around 2-3 inches. Today I got my shippment of 2 other goldfish : a blackmoor and a ryukin. They are a little tinier than the fantail and they accommodated pretty well in the tank. My problem is that I saw my fantail behaving weird now. He follows the new fish (non aggressively)and now his pectoral and dorsal fins are folded. I tested the water and it was perfect. Could it be that my fantail is stressed because of the new fish? Please help!