cool...make sure fishy don't jump out. Not all of them are right in the head
Yeah I've had a
betta jump out before, checked my tank parameters to make sure everything was on the up and up, tank was fine, betta was just insane (she was fine, btw, it had just happened when I walked in and I put her back in the tank.)
Then at petsmart I had 3
platys jump out, right after the other, right in front of me. They too were fine. Checked the tank parameters there too, everything was fine, except their water was about one degree
cooler than usual, which doesn't seem like enough to make them go berserk and make a jump for it. They do however tank hop all the time over dividers despite the dividers being an inch and a half over water level. Just to go join some buddies or whatever the next section over. I don't get the jumping to their deaths though.
Many years ago my family had a 100 gallon full of primarily
cichlids and a few
plecos, and I can't tell you how many of the
convict cichlids hopped out behind our tank. It happened while we were gone a lot so we didn't always find them in time. Some fish are just bonkers and go on suicide missions. The weird part is the only opening was a small gap right in front of the filter and they still managed to hop out towards the back!
I am certain to secure all of my tanks to have as little opening in the hood as possible, I've even used filter floor in some spots where it was not possible to do anything else. You just never know who's gonna decide jumping is a great idea!
As for filter silencing, I use
filter floss in front of my cartridge to slow the splash out and keep my water to about half an inch below the filter output. I have seen some people cut a 20oz bottle in almost half or 3/4 , cut a hole or slot for water to run out, and fix it in place right below the output. It works well but I'm hesitant to do it because I don't know if the plastic over time would leech anything out into the water. It's unlikely but I'm always overly cautious with my fish because I name them all and get attached and end up treasuring every one of them lol.
It really does work well though for any waterfall noise. I don't mind some trickling as I find it peaceful, I just don't like loud splashing which occasionally occurs with my
biowheel. Sometime stopping it, turning it in the wrong direction and letting it resettle helps, but mostly it flings water which is noisey. Anything that slows the output helps you just have to make sure not to slow the filtration rate too much.