i have a 4 year old male fantail goldfish. about 6 months ago i bought a female black moor to go into a larger tank with him. my new tank is 30 Gal. everything has been going smoothly until this week. Titan (my white fantail) has started chasing Kiwi around and hes even caused her to hurt some of the scales on her side and she has a slight rip in her dorsal fin. all i have in the tank is soft plants and a very small castle. I cant figure out why his behavior towards her has changed to aggressive. but if anyone has any ideas id love to hear them.