tank size for rainbow shark? why'd my last one jump?

[rosie]

hi i'm new. thanks in advance for the help. i'm new to tending an aquarium. please help....
about my tank: i have a 20 gallon freshwater. so far i have 7 barbs (3 different kinds, totalling about 9in worth of fishies) and a little algae eater (another inch).
i recently got an albino rainbow shark. it jumped out the tank its first night there- found it dead in the morning . (i have lids but there are small open gaps on account of the filter and heater hanging over the edge).
i'm bummed about the jump but am also tempted to get another lil' rainbow shark and do something about covering up the gaps. but i don't wanna if my tank is just too small for that kinda fish. fish websites recommend a minimum of 50 gallons. for real?! i just really liked that fish and want another. but not if its gonna be miserable and always wanna get out.
so... 1) is my tank too small for that kinda fish and 2) why do y'all think fish jump? i feel bad keepin a creature if they seem like they feel locked up and just wanna get out.
k, thanks, rosie

 

[zephyr]

I really believe it jumped because it didn't like the tank or your face! Ha! I'm joshing ya! They just dont do it for those reasons. Some fish just love to jump! All fish have different personalities, so some rainbowsharks will wanna jump, and others will just go "*beep** it!"
I think a rainbow shark would handle a 20gallon while it grows, but when it gets full size it will probably need bigger. I rekon you shuld cover the gaps, and give it another shot. But if the fish knocks itself unconcious, i'm not giving it mouth to mouth! Haha!
Hope this helps
Justin

 

[Voodoo Chilli]

Have you tested for ammonia and nitrite lately? Fish will literally jump out of tanks that have enough ammonia and/or nitrite in the water to cause them stress or pain. Of course, some fish do jump for no reason (or at leat no reason we can understand) and he may have simply been unlucky enough to jump near the opening.

I'm not sure I'd add another rainbow shark to your 20 gallon. It just doesn't provide enough room for them to feel comfortable (which is another possibility for why he jumped).

 

[sweetsuvvyb]

Just as an FYI too...the 1 inch per gallon rule doesn't really work all that well...you kinda have to take into account the fish's behaviour, eating habits (ie, if they are a "messy" fish), as well as how big it's gonna get.