Actually you'd be surprised how far they can jump even with the long tails! I had a long finned boy jump on me once and the poor thing, I found him a little too late and he didn't last the night
But my tank is about an inch below the top but my mesh goes right up to the top part of it and then I have a glass canopy which sits right on that so literally they can't jump over because there's no space so that's why it's up a little more. But before when I didn't have the canopy, it was down about 2 inches and I never had a problem, even with the short fins but sometimes you just never know!
Rembrandt II, Suiché
Leopards: 1:4 Hawkeye, Luna, Astrael, Dorian, Cullen
Gargoyle: Cloudjumper and Toothless