What size tank do you have? 20 gallon per fish for life is the general rule of thumb..The tank footprint is one of the most important things to keep in mind..Piranhas need a long tank not tall..Also when getting pygos 2 is a bad number you should get a third to spread out aggression.
Food--Depending on the size of your fish can range from blood worms,,beef heart,,white fish(catfish tilapia shrimp etc)
Temp-- 78 to 82 degrees
Water treatment---I suggest just keeping the tank clean and free of excess food..Do atleast 1 water change of about 25% weekly.
that looks to be a 30Gallon tank..........????????
too small for juv reds, you can start out with babies but you will have to upgrade
to a bigger tank in no time flat. if you plan to keep reds (pygo's) no less than a 100
gallon will do (imo) 75's are usless
That's awesome news! Since you are getting the 150 gallon, it would be a perfect time to purchase some more juvenile red bellies the same size as the ones you have now. You can keep 8 for life in a 150 gallon tank with good filtration of course. It sure beats a shoal of only 2!