Is my tank setup poorly or do Cory’s have an innate sense of death.
I’ve had this tank setup for 8-9 months now and I’ve only had this problem with Cory’s, more specifically Orange Lazer Cory’s. I attached a picture of my full tank and then the spots Ive found Cory’s stuck, some alive, some died being stuck. Out of my original 5 Lazer Cory’s, 2 died from being stuck. One of them moved the sand from under the quartz in the corner and wedged itself between the glass, sand, and rock. Another one I guess was trying to surface for oxygen and wedged itself between the glass and wood. The last one which I found alive still was wedged between the glass and heater. It’s only my Lazer Cory’s that do this, I have Paleatus Cory’s since day 1 and they’ve never gotten stuck or wedged. Is my tank just setup poorly for fish getting stuck or am I just unlucky in finding some dumb Cory’s. None of my other fish have gotten stuck anywhere or had issues traversing the tank, just my Lazer Cory’s. Is there anything I can do so they can’t get into these small gaps? I know quarts isn’t the best to use in tanks cause it’s sharp and I plan on replacing it soon.
Edit: 7.0ph - 0ppm ammonia - 0ppm Nitrite - 20ppm nitrate - dKH 2 - dGH 5