I have a good number of tamed cats, but they just won't breed. I've tried both cod and salmon, and one the first cat, the love hearts show up, but then when I try the next one, the love hears just stop, and the cats don't even act like they are in love mode. Plus, the cool-down seems to end quite earlier than normal. Could someone please explain what is happening?
(Note: I have noticed similar issues to this problem in searching for this issue beforehand, but the problem is slightly different to mine.)

Edit: I figured out the problem: the cats weren't sitting down. Whoops!