Epalzeorhynchus frenatus

[bpb21]

I've got a question about "jumping" behavior of fish. I've read (and heard) that the red-fin or rainbow shark tends to try to jump out of aquariums. I've always considered it a general rule that if your fish are trying to jump out of your tank, your water quality is way off.
I've had this particular rainbow shark for over a year, at all times in a completely uncovered (no lid whatsoever) aquarium, and it hasn't even made a pass at the surface once! This tank, by the way, is 17" x 12" x 24". Anyway, am I right in assuming that jumping is caused by adverse water quality, or does it just depend on the fish in question?
(I've also read that even the common pl*co will attempt to jump out of a tank, but I've had one of these for even longer and I don't think it's been over halfway off the bottom of the tank; I flat out don't believe the pl*co will jump unless it's in a chlorine bath or something)
If anyone can set me straight on jumping behavior & fish, I'd appreciate it!
BPB21

 

[Lateral Line]

There are very few fish that fall within the remit of this forum that don't jump if the mood takes them. Some are greater jumpers then others, true.

For some fish, jumping is an escape ploy to avoid a predator or something else that is bugging them. Many fish jump if irritated by a parasite, Ich for example - they have an itch and it helps scratch it. Some species use jumping as a food gathering strategy. Still others jump in order to lay their eggs. Some fish just seem to flash around a tank and finish with an airborne flourish for no apparent reason - perhaps it is a display instinct. None of these are a reaction to water quality.

I'd like to think the water quality in my tanks is pretty good at all times, but still have the odd jumper.

As with any advice, there are people who get away with not following it for years, but ultimately the advice I will give you is that a well fitting cover is a very good idea when keeping Cyprinids and Characins.