I'm not so sure that a slurp gun will work for you. It usually is at least 2.5 feet in length nad the plunger extends out the same distance. I don't think you'd be able to get it in the tank and use it correctly to get the fish...and by the time you try to get everything arranged, the fish would be hiding. I have a slurp gun that I purchased in 1990, and if you are in Austin, you are more than welcome to try. It might need some new seals, and I can check that out.
“Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.”
-Jim