I have seen folks take a established rock that has a hole in it, place it in the center of the tank area. place a plastic soda bottle cut in half and then shoved back together with rock n em inside, with small holes in it over the rock the BTA and leave it there till the NEM attaches to the rock. then place said rock where you want it making sure the rock is the highest spot around. They will climb to the top to get more light regardless of how much light you give with in reason of course. Huge ones will get thru just about any normal intake mesh. down to about 1/16 of an inch. go right thru 1/4 over flow teeth for sure. cover submerged pump intakes with simple polly floss or a old sponge from an old HOB filter with a hole poked in for the intake tube. comb teeth are a bit harder as messing with them raises the water level and effects a ATO system as well as it gets dirty. They will still let go and walk if there not happy or if its a lunar eclipse or if you forget to wash the soap from your dishes before you make a meal. There weird like that.. mind of there own sometimes. Then they split into two and it starts all over again with twice as many to deal with. Ohh they sting everything as well don't forget. lovely little critters.....