I got 10 gallons of tank for my son's xmas gift. One day we went out to get a fish for his tank (after the tank was set up). We got red fin shark. Then put the shark in the tank sure he was trying to hide but no luck. He fed him and that nite, he went to bed. The next morning, my son came to me and said I cant find the shark and I said it should be there. So we went to look for it and couldn't find the shark. Hummmmmmmmm where have he gone to. Maybe my cat got him, ofc
I was pissed and started to yelled at my cat. 
About 1/2 hr later, my son came to me and said I found him. HUH??? Where??? So he showed me and it was on the floor, dead already. HUMMMMMMMMMMM. How the heck the shark got out of the tank. I couldn't figure out. So I went into the website and look and look and look. AH UH!!! There, yep that red fin shark sure is a jumper.

So I went back to the tank and look around where he would have jump out. Hummmmm yep thru the opening where the filter is. Hummmmmmmmm what can I do. Thinking, thinking, thinking. Got an idea and went to the store brought another shark and screen. We came home and I cut out the size of the opening where the filter was and cover it up with tape. Now put the new shark in the tank. HAHAHA sure he found an opening but can't jump out.
It works!!!!