Angelfish and Tiger Barbs

Question
Good day!

We really need your expertise regarding our brand new 72 gallon freshwater tank. We are fairly new at this and have successfully cycled a 29 gallon planted aquarium (4 tiger barbs, 4 long-fin rosy barbs, 1 pleco, and 1 tri-color shark). With our first tank, we tested the water everyday and did so much research regarding the nitrogen cycle that we could predict when the nitrite levels would peak and begin to drop...

Sooo... now we have purchased a 72 gallon tank to expand our hobby. I would love to make it a community tank with maybe 4 angelfish but we are also thinking of breaking down our 29 gallon and POSSIBLY putting our fish into the larger tank after it cycles. I've read that if I have more than 6 tiger barbs in the tank, they will not harass the angels.

Also, I heard that if you multiply the length and the width of the tank and divide by 12, you can calculate the total inches of fish that will fit in the tank. I received a calculation of 92 inches. I've calculated the total inches of FULL-GROWN fish planned for the community(we hope they stay with us for a long time) and it totals about 88 inches and it is about 19 fish. Do you think this is too much? Also compatibility of the fish is very important to me.

Any advice is appreciated, thank you!

Answer
Hi Therese;

Wow! You've really done your homework! The surface area calculation makes good sense if you want to go by that figure. I generally just go by the "one inch of adult fish per gallon" and don't get close to it for safety reasons and convenience too. If the tank is at it's maximum, there may be squabbling among the fish and any problems with water quality or illness have to be remedied immediately. I like to keep my tanks stocked low so there are fewer potential "issues". For fish that get larger than the average small community fish, such as bigger than 3 or 4 inches, or are deeper-bodied fish like goldfish or cichlids, you can't follow the one-in-per-gallon rule. The fish you have suggested so far would be okay though.

You are quite correct about the tiger barbs. The more the merrier. They distribute their nastiness amongst themselves instead of targeting other fish in the tank. There are exceptions to every general rule though, so if you do decide to do that, watch them. They can be little devils!

Have fun and keep up the good work!

At Your Service;
Chris Robbins