Im not a behavior biologist either, but I have spent a lot of time around fish and ive spent a lot of time talking to and helping people that care for fish. (Former petstore fish guy that took his job too seriously)
That fish is having fun, and fish absolutely DO have fun!
There was a regular who came into the store I worked at a lot, and he kept several varieties of chichlids, a very smart, aggressive type of fish.
He would come in and talk to me about all the drama his fish get into. The different territorial disputes they were having, who had paired off with who, who broke up (yes chichlids are like this)
But he had a jack dempsey in particular that LOVED to chase his hand around the tank, not his wife’s hand, not his friend’s hand, it HAD to be him. He said that as soon as he entered the room where this fish’s tank was kept, the fish would TEAR UP the tank decor, knocking things over and acting a fool off his shits until this dude stuck his hand in there and let the fish chase it around back and forth.
He theorized that his fish learned that if he knocked the tank decor around, his owner would obviously have to stick his hand in to fix it. So when he wants to play “chase dad’s hand” thats naturally how he knows he can get the hand to appear. He wont do this behavior for anybody but this one guy and he won’t tear up the tank anymore after he had received sufficient “play time”, usually once a day when the guy got home from work. He likened it to having a dog that wont leave you alone till you play tug o war for a bit.
I had a betta that would spend twenty minutes at a time just swimming up to the waterfall of the filter, letting it push him down to the bottom of the tank, only to swim back up and do it again, like it was a fucking slide.
Bettas are weak swimmers, and they dislike strong currents, but this guy was using the filter current like a slide. Kinda like how we don’t really like getting thrown around, but we still enjoy rollercoasters.
I also have countless stories about goldfish trying to “give hugs” (re: shove themselves into their owners hands during tank maintenance)
My betta knows how to lie and he will only beg for food in front of those he knows have not fed him yet.
There is so much evidence I’ve seen that fish are waaaay smarter and affectionate than we think. They absolutely have fun and I honestly don’t think enough studies have been done on fish brains and fish behavior in general.
And honestly, having worked in a pet store, fish are generally treated like they don’t have brains by even the fish care brands that claim expert knowledge.
Its definitely worth noting that hard scientific evidence presenting that the very opposite is true would probably lead to more robust animal welfare laws that would definitely upset the aquatics industry. Food for thought.
