I spearfish mainly. Since you got way off track, I also collect fish. I decompress my fish like a diver would decompress. I use a jug to mark the spot, and the cord is just a few feet longer than the depth. I have several jugs with the depth written on them. The line has loops about 2 inches long at 6 foot intervals, and start at 1/2 the water depth. For instance if I catch a small angel or chromis in 50 ft, I put it in a jar, and into bag(to keep mackeral from trying to eat them, and stress out the fish) and clip it to the first loop at 25 ft. Every 10 minutes I move it up. Do not do this on your anchor line. It takes about an hour to deco a small fish from 50'. If larger more time. On this coast-West Coast of FL, we have 4 species of Chromis, 3 of which are only found in 100'+ depths over coral reefs. These need about 2 hours of deco. Just like a person that had been down for way beyond their deco penalty. Only blennies and gobies and a few other, such as toadfish and batfish dont need to be decoed. Never use a needle. It may work on a large grouper, but not on a small little fish. Just take the time to deco and you wont have them floating in the bucket, dying at the surface. If less than 30 feet, you should be all right, but keep an eye on them. If they start floating, or acting like they cant swim right, take them right back down, and deco. I used to live on Oahu, and collected for a living there, and here in Florida before a RS and ML permits were required.