Pacu~Silver Dollar compatibility

[ErinGoBragh]

Just a quick question,
I had 3 sliver dollars in my 75 with a pacu, and they all got along together fine. I added 2 more red hook sliver dollars today, and all of the sudden the pacu started acting like a complete jerk. he has chased the red hooks almost non stop for the past 3 hours or so. I finally turned out the lights and shut everything down to hopefully give him a rest. So, basically, is the pacu just acting up to establish the pecking order, or is he just out to eat my new red hooks?

If he is just out for an expensive meal, he will go to the lfs tomorrow. if not, I would like to keep him around. they are all about the same size, thats why I am not sure if its a dominance issure or not.



BTW, the pacu is not a black pacu, or a red bellied pacu. he is only supposed to get to a max of 8" according to my lfs, and for a very long time I have brought fish home, watched them grow (usually for years) brought them back to the lfs in trade for new fish (again, to watch them grow), where they either get sold to someone with a very large tank, or to live out thier lives happily in one of the display tanks. Sorry for the run on sentence, but I had to get that out. Hopefully this will prevent the "but with the fish in your tank, you need at least a 20,000 gallon tank when they mature" replies.

Thanks for the help!

[usmc2b2004]

How long has your tank been setup? Most of the time it's a bad idea to add any new fish to an established aquarium.

[reefmanwannabe]

OK your first mistake was listening to the guy at the petstore . I've kept Pacu's for years and the only one they sell at pet store's ( as far as I'm aware of) is either the black or the most common red bellied . The one I used to have was 27" when it died .
Pacu's are pretty territorial and will try to kill anything and everything in the tank . The only thing I had in the tank was a clown knife fish , it was to flat to bite . I noticed when they were small they didn't seem bother anything but really started getting aggressive once they got to about 5 inches or so . Don't believe that its going to stay about 8 inches , its going to get a LOT bigger ,they average 2 1/2 -3 feet long .

[ErinGoBragh]

Originally Posted by usmc2b2004

How long has your tank been setup? Most of the time it's a bad idea to add any new fish to an established aquarium.

The tank has been set up for a couple years, but the fish are all fairly new to the tank. They seem to be getting along now, but I am still going to keep an eye on them.

[ErinGoBragh]

Originally Posted by reefmanwannabe

OK your first mistake was listening to the guy at the petstore . I've kept Pacu's for years and the only one they sell at pet store's ( as far as I'm aware of) is either the black or the most common red bellied . The one I used to have was 27" when it died .
Pacu's are pretty territorial and will try to kill anything and everything in the tank . The only thing I had in the tank was a clown knife fish , it was to flat to bite . I noticed when they were small they didn't seem bother anything but really started getting aggressive once they got to about 5 inches or so . Don't believe that its going to stay about 8 inches , its going to get a LOT bigger ,they average 2 1/2 -3 feet long .

I have been dealing with the guy (owner) at the petstore for about 19 years...I will give him the benefit of of doubt. I called him today to let him know what was going on, and he said to keep an eye on them and if the Pacu starts getting aggressive again, to let him know, and if need be, he will drop by after hours to pick him up. The only time I have ever had a problem with this LFS is when he stopped carrying saltwater fish and I had to get livestock and advice from others. In an odd twist of fate, that poor advice from the other shops is exactly what brought me to this site a couple years ago in the first place.

Regarding the Pacu, I forgot to ask him the scientific name today when I talked to him, BUT his markings are nothing like red bellied or Black pacu's. When I remember to ask, I will be happy to pass the information to you.

[usmc2b2004]

Or if you could snap a quick pic. That might help with the ID of the Pacu.

[ErinGoBragh]

Originally Posted by usmc2b2004

Or if you could snap a quick pic. That might help with the ID of the Pacu.

That had crossed my mind. While I have finally learned to use the whole "digital camera" thing, my wife has the usb cord at work. whichever comes first, a name or a pic, will get posted...maybe this weekend.

[ErinGoBragh]

Actually now that I have had time to check things out, he is not technically a pacu, he is a spotted silver dollar. I guess they are fairly commonly refered to a spotted pacu, since their shape is somewhere between the silver dollar and the pacu.


notice behind the dorsal fin, the spotted silver dollar is longer than the plain silver dollar in the background.


Well, they are playing nice now, and they are closer related than I thought so I guess I can breathe a little easier now. I am still going to keep an eye on them though. -=Edit the pic didn't upload, here is a link http://images.google.com/imgres?imgu...a%3DN%26um%3D1 hope it works!

[usmc2b2004]

Silver dollars and pacu are pretty closely related, but once again they can become aggressive, but on that note most fish do get aggressive with age and size. But for the most part as long as the fish grow up together they should get along fine... i.e my mother in law had neon tetra's with a 8 inch oscar with no problems but they were put in at the same time......

[ErinGoBragh]

Originally Posted by usmc2b2004

Silver dollars and pacu are pretty closely related, but once again they can become aggressive, but on that note most fish do get aggressive with age and size. But for the most part as long as the fish grow up together they should get along fine... i.e my mother in law had neon tetra's with a 8 inch oscar with no problems but they were put in at the same time......

I knew they were, both characins (sp?) I think, but closer related than most of the other tetras. Your mother in law must have never fed the oscar live fish? Thats certainly not what one would normally expect. Even if he never got aggressive, you would think he would have eventually decided they were food rather than friends. id would make an interesting picture for sure.

[usmc2b2004]

No she actually never fed it live foods, she's a real softie. I couldn't believe but low and behold it is actually true. But I think you will be alright as long as there are hiding spots in your tank. Keep use posted on the out come though.