Every now and then I have an experience that seems worthwhile to share with other people, in order to spare them a little pain, and this discussion of the proper use of 'fish traps' is one example of this sort of thing. I have a planted tetra tank, and I put a few swordtails into the tank, because I like swordtails. I assumed that some of the bigger tetras would handle the population control problem, but this turned out to be false, and to many baby fish were surviving and growing to a large enough size to become inedible. I found a real cheap 75 gallon tall including a stand and an old Fluval 304 on Kijiji for only 200 bucks and so I made plans to move the swordtails to a new tank. Because the tetra tank is a very mature planted tank, it is not possible to catch fish in nets and move them to the 75 gallon, so I had to purchase one of those fish traps (you hold a string and then drop a trap door when the fish you want swims into the trap to eat whatever snack you placed within the trap to act as a lure). I had five swordtails in the tank, and catching the first three was no problem, but catching those last two turned out to be a long running nightmare that dragged on for hours as a I was forced to sit beside the tank holding a string and waiting and waiting for those two fish to finally go into the trap. It turns out that if you want to trap fish, you must be smarter than a fish, because trapping a fish should not drag on for hours and hours, but should only take maybe about 60 seconds tops. What I discovered is that if I gave up and just went away, the swordtails would head straight for the fish trap. If I approached the tank they would exit the fish trap. Some scientific experiments have been conducted on fish that show that in some ways the fish is smarter than a cat or dog. The fish has the ability to learn by watching and by imitation, an ability only possessed by certain primates, like chimps, and human beings. I always knew that fish were smart, but I guess I just underestimated just how smart they really are. After watching those first three fish get caught in the trap, which took no time at all, those last two, having watched that process and figured the whole thing out, were not going anywhere near the trap. So what I did was I ditched that door attached to that string, and just left the trap open. I then got a clean cloth and soaked it in water at the sink, put some bait into that fish trap. My tetra tank is backgrounded on three sides (it looks like a black rocky cove) and so what I did is I stood off to the side where I would not be immediately visible and where I could peak down into the tank from the top down and watch and wait. What happened was that the swordtail would swim up to the front glass of the aquarium and scan the room to see if I was close by, and not seeing me around, and seeing that everything checked out and the coast was clear, the swordtail would waste no time and would swim right into that fish trap and start eating that food that was left in there. I then lunged forward and rammed that wet cloth into the opening of the trap and those last two swordtails were moved to the 75 gallon tank. The process of trapping fish did not take hours, but somewhere between 30 or 60 seconds, because as soon as those swordtail fish saw that I was gone and got the all clear to go into that trap, they immediately went into the trap. Fish are smart. If you want to trap fish you must be smarter than the fish. Just thought I would share this just in case someone someday might be spending hours trying to trap fish, when, really, you can do that in seconds if you understand just how smart a fish is and how quickly a fish figures out the rules of the game of that fish trap business. Just a few side comments here. The old Fluval 304 is a nightmare to first get started. Priming the tank is dreadful. I tried holding up the intake tube and filling it with water through a funnel, and I tried using a power head to pump water into the intake hose. I am not sure which one of those things I did actually worked, but suddenly after a grueling ordeal, that filter surprised me and actually started to work. I never want to prime an older designed fluval again. I also thought that I would mention that I am jump starting the 75 gallon using Seachem Prime (which includes an ammonia and nitrite lock which detoxifies these compounds until filter bacteria process them) and I am also using Seachem Stability (which contains the inert spores of selected bacteria which 'hatch' when introduced to the aquarium and quickly colonize the filter). I have used this technique to avoid the 'new tank syndrome' for each aquarium I have, and it works perfectly. I thought I would mention this because someone at work suggested that I torture some cheap fish that I didn't want to get my 75 gallon fluval filter started, which is archaic and badly outdated advice.