A very fine reply from one of our more Expirienced Members and a good PostBeef heart should not be given as a normal diet. Beef heart is flesh of mammals and this fat is different that fat from fish flesh. It can seriously upset the system of fish if given in high quantity. Some even die, such as L134 witch are very sensitive to this.
Beef heart fat solidifies below certain temperatures and so blocks the digestive system of the fish.
I have heard and seen that beef heart is given to young discus to grow faster. But is this desirable? I find that fish need time to grow just as we humans. I think it is wrong to pressurize fish into growing faster and bulkier. I know that a well known discus breeder in Germany feeds his young discus beef heart to get them growing faster for sales.... When adults these fish are extremely heavy and robust, just like body builders. I don't think this is natural anymore :wb:
I don't feed any of my Lnumbers beef heart as I think it is very bad for their health. I do occasionally feed it to my discus as a snack because they do like it even if it's not good for them.