(for the record, I already attempted to ask this in the physics stackoverflow)
I'm attempting to create something similar to a vertical multi-siphon. The device would pull water from multiple sources, at multiple elevations (a total range of about 5 feet) up to the top source so it can redistribute down again.
This could be simply accomplished by (a) pump(s) or a mini-turbine, but the transfer medium should be about 4 inches diameter: about large enough for a Betta fish to move up.
I can't use a multi-siphon going down and just out-pump the down flow of water, this means the fish would have to fight against the current up the piping so this isn't really an option.
Chemical and thermal lift are also not feasible to move the fish.
The only thing that is currently coming to mind, is use airline tubing connected to a pump to pull the water from the point at which the "siphon" was primed.
Continually applying negative pressure might be enough to pull the water at a rate that isn't going to vacuum a fish. Though, I'll admit I'm concerned it might need a series of pumps like this to imitate a caterpillar propulsion system.