The fish: 9 female bettas and an indeterminate number of ghost shrimp. The tank: A 20 gallon long tank with OPS and a gravel cover. The gravel cover is just thick enough so that the tank is a sort of murky brown (I did this intentionally figuring lower visibility would reduce aggression). The tank is heavily planted, so with the low bioload water changes come on average every two months, but I determine this with weekly testing. I have 2 Floramax bulbs (doubled down because of the gloom and because all the LFS in the region decry them to bad to carry, but hey I had the extra strip light and they were on clearance at Petco 2 bucks each) on a 12/12 cycle. Plenty of hiding spots including some floating ones. The filter and heater are the standard Aqueon set that come with the tank. So my problem is that one or more of my ladies seem to be jumpers. One tries to jump out at feeding time, but almost always aims right into my hand so maybe she's just clever and greedy. But both day and night I can hear the little splashes caused by whoever is jumping. Could this mean tgey are unhappy, or do some bettas just jump? I think the filter is a little fast for them, so I was thinking I should downsize to a submersible rated for 10 gallons since Ive noticed that no one's territory involves the hiding places closest to the filter. Would the lack of falling water encourage them to spread territories out and would that make them happier? Would introducing a flow underwater interrupt their established territories? Or would it only help because I'd be able to cover the entire tank?