Telling aggression from play with Angelfish
Up until they reach about 3" body-size Angelfish are classed as juveniles, some measure differently, some go by when they pair. Granted, my info is from back when I bred them 20 years ago but, this was the deciding size back then. Anyway, I learned a ton about their behavior from the five years I bred them.
How to tell one from another? Well, fin-nipping and Lip-Locking are sure signs of Aggression but, Juveniles, especially ones that were raised to sale-size in the same tank also play. This is all referring to Juvenile Angelfish so, please remember that as I explain.
Angels that grow together often times develop games, mostly a form of tag, where one will come up and tap the body of another with it's mouth closed. At this point the tankmate will turn and give chase and the game is on. This can go on for as much as fifteen minutes or so then, the next time you look they're swimming around together. I've seen as many as four playing this game. Distracting to the others in the tank but, harmless.
In my tank(All my Angelfish, both the Black and the Marbles came from the same breeder. A gentleman I've known since I was breeding). All are Silver-Dollar sized Juveniles. Two of them, a Marble-Veil and the Black, have upped their game. Now, it's ambush. I have been watching these two bozos for a week now doing this. One will try to hide and wait for the other to come looking for him. Then he'll dart out, tap the target and take off. They are fast learners though. Day before yesterday, the Black was hiding in a cave structure and tagged the Marble. Last night I looked and there was the Black inside waiting. But, the Marble, as I watched, came around the rear of the tank, came into the backside of the cave and tagged the Black! He flew out of the cave(The Black) so fast I thought he was gonna knock himself out on the glass! He turned,went into the cave and the Marble flew out the back! Pretty comical.
Aggression, most times you see this in Angelfish purchased in a petstore, especially chainstores like Petmart that may get their stock from many different Breeders. These fish have the need, being cichlids, to quickly develop a pecking-order in a tank. They use aggression to do this and, sometimes it doesn't stop. Being what they are, a little should be expected. But, constant warfare is not good. The main instigator can usually be spotted right off and, unless he's a prime breeding candidate, should be either retanked or rehomed. Usually but, not always, tankmates that grew up together don't exhibit much aggression unless there's an underlying problem. Water conditions and disease are the two biggest contributors to tankmate aggression. Stress from water conditions or disease can make them irritable and grouchy.
A big key in keeping aggression under control is Water-Temperature. Angelfish that fight like Gladiators at 78F are just as healthy and a lot more peace-loving at 72 or 73F. The temp doesn't stress them at all. AAMOF, it's healthier because the slightly cooler water holds more dissolved oxygen. See, the Temperature-key is tied to breeding, males start vying for females even as juveniles, although I don't think they really know why yet. The higher temperature fires up the hormones. So, stop that from happening. I used to condition breeding pairs for two weeks at 73F with a lot of high protein foods. Then, I'd jack the Temp up to 80 and they'd breed within two days. As soon as the fry started feeding on their own, I'd move the parents to a 'Recovery-Tank' and slowly lower the temp to 73F again so they could get a rest and get healthy. Typically, I'd breed them every five weeks(I had five breeding pairs so, I had a pair breeding every week while four others were in various stages of getting ready).
Now, there are probably as many differing opinions about this as there are hairs on a dog. All I've stated was gleaned from personal experience and remember, my experiences are 20 years old. It's been amazing to me how the hobby has advanced since the last time I was into it.
Hope this helps somebody.
Last edited by Dave Waits; 11-13-2012 at 06:49 PM.