As some who know me, I have been dealing with large piranhas 12 inches to 17 inches for the past 10 years or so and I/ve tried various methods of getting them out of the tanks and into other tanks or just for moving them elsewhere. I have found my latest method to be the least difficult for me and the fish. This especially applies to moving this 17 inch rhom around. Have the tank prepared to be able to place a large bucket in. The bucket I use is a little taller than your average aquarium bucket. My bucket is 18 inch tall by 12 inch wide with lid. This really works well in solitary fish tanks as you only have to concentrate on one fish at a time. Slowly and without much commotion, place the bucket into the water horizontally until the bucket sinks as the water enters it. Make sure the bucket open end is facing the piranha. Slowly move the bucket towards the fish thus leaving it no room to escape but into the bucket. Don't force the issue by using the bucket to cover the piranha. Instead, gently using long net or any other instrument, nudge the fish into the bucket very slowly. Once completlely in, place lid to cover bucket opening while bucket is still horizontal and when lid is secure and tight around bucket it is time to lift bucket out of the water. At this junction it is best to have someone help you lift the bucket because the combo of weight and the awkward angle of lifting all that weight over you body is rather taxing! Once the bucket is out, you can move it to wherever and simply place the bucket with fish in other tank. Place the bucket upright fisrt in the water and than horizontally and than realease the lid and the fish will come out easily. No water splashes, no ripped nets, no damage to fishes body or fins. I have done this four times in the past year and everytime it worked great. As a reminder, this really is good for solitary fish tanks with little or no decorations to get in the way of and the bigger the piranha the better. It worked well for me whether I was moving the rhom from my 10 ft long 30 inch wide tank or from my 180 gallon tank! I hope this helps with those guys with the big boys!