I came back to this forum just for this thread!
I moved a few months ago and this house is 100+ years old, not level, feels a wee bit unstable. Anyway, a week ago we had 2 decent sized earthquakes in one day. I wasn't in the house during them and didnt feel them, but I was told the house literally swayed back and forth. When I got home all fish (bettas, tetras, rainbow fish, pencilfish, etc) were injured in some way. Missing scales, torn fins, scrapes down their sides. My favorite betta, Spike, was propped up against plants and had minor tearing in his fins but seemed to be the least damaged. Turns out the damage was internal, probably from being slamed against the glass or wood. Cue loss of appetite, sudden inability to swim, seizures, and death. If any of you watch The King of DIY on YouTube, it was like Buddy dying but tiny fish version.
Now my giant betta, Stormy, seemed to be only externally damaged. Scales torn off his face, scratches down his sides, torn up fins. He looks like he went head first into rocks or glass for one earthquake and got dragged along rocks or gravel for the other one. I wasn't super concerned about any of that because healing up moderate external damage is pretty darn easy. Well, the next day he stopped eating and just hangs around the bottom of the tank. Hopefully he's just super stressed, but I doubt it. He doesn't even want bloodworms. All bettas want bloodworms. I've dealth with earthquakes before and the fish are annoyed, but this is the first time they've gotten seriously internally injured. I can't imagine how roughly the water in the tank is sloshing around if the entire house is swaying. Clearly it's violently enough to slam a fish into glass or decor hard enough to damage organs, or at least enough to cause them to jump, hit the lid, then freak out and hurt themselves further.
Fricken earthquakes are killing my fish and now I have to figure out how to do earthquake safe aquascapes that will minimize future damage. On the bright side, spending hours meticulously cutting the lids for a super tight fit really paid off. If I was lazy the floors probably would have been flooded.
SIP Spitfire, Dyson, and Spike