Please visit our Sponsors
FAQs on Pacus, Colossoma Species

Related Articles: Serrasalmine Fishes, Piranhas, Characoids/Tetras & Relatives

Related FAQs:  Serrasalmine Fishes, PiranhasSilver Dollars,

photo permissions     5/14/16
I'm a biology student who makes non-profit educational web comics to bring science to a public audience. You can see some of our work here: www.squidtoons.com.  I was wondering if I could get permission use your photo of the jaw of a *Colossoma sp* fish for a comic about the life history of the Amazonian Tambaqui? Specifically this picture (
on this page: http://www.wetwebmedia.com/fwsubwebindex/fwdailypix/fwdp%20arch%2013-25/fwpotdarch20.htm.
I will of course provide a citation.
Much obliged,
Bethany Kolody
<I do grant you said permission; per my/our Content Use Policy:
Please do send along a link to this work.
Thank you for your efforts. Bob Fenner>
Re: photo permissions; Colossoma f'    6/17/16

Here is a link to my comic.
<Thank you, Bob Fenner>

Red belly Pacu; hlth.       5/4/15
Please HELP>>> our Pacu named Bubba is 10 years old and lately he has been having problems. About a month ago he stopped eating and breathing rapidly,
<Bad... what have you fed this animal the past decade?>

so we started to investigate his tank further. He is in a 75 gal
<Too small>

tank by himself the temp is 75 degrees water conditions are fair hardness is a little high, and so is the nitrites.
<Toxic... the environment is the problem here>

We are treating the tank
<Of no use; counter-productive. FIX the environment>

trying to get things back inline. we did a 50% water change 2 weeks ago.
Now he is pale and has bumps on the front of his face, We've had him for so long I don't want to loose
<Or lose>
him, but I don't know what else we can do to help him. Any advise would be great.
Thank you
Cheryl Me guess
<See WWM re Colossoma.... Here, I'll link it for you:
What do these fishes need? SPACE, soft-acidic water, NO ammonia or nitrite, less than 10 ppm NO3, vegetable foods, frequent partial water changes; current. High consistent DO.... What will you do?
Bob Fenner>

Pond Fish Question. Colossoma beh., Pangasius comp.    3/22/14
Aloha WetWebMedia crew, Thanks in advance for your help. I've recently been given 4 Pacu approx. 8 inches in length.
<Aye ya... you know these Colossoma sp. will get much larger?>
They seem relatively healthily ,although they have been housed in 75gal aquarium(these are terrible aquarium fish for the record) . Hopefully they are not stunted. I was told by the previous owner they are less than a year old. These fish managed to crack their glass lid and the owner was concerned about them separating the seams of his aquarium. I'm currently housing these Pacu in a 350gal quarantine tank filtered by an aquaponic grow bed. I've been feeding these guys Hikari cichlid pellets, algae wafers, duckweed, red bell peppers, peas, carrots, Asian spinach and etc.
I have a few aquaponic ponds on my property, so people always end up giving me their tank busters. I currently house a few Pangasius, Pimelodus clarki and channel catfish. So these Pacu will end up in a 1800gal reservoir, all to themselves(if you have any
suggestions on tank mates let me know). My question to you is, I've noticed red gravel showing up in my tank.(of course they came from a tank with red gravel) I know these fish are defecating or throwing up this gravel. It has been going on for a couple weeks, and is getting to be less. Have you heard of this and should I been concerned? The fish do seem healthy with big appetites(water parameters are in check).
<Have heard of this... passing of ingested materials... these animals chew off the pericarp of seeds in the wild... are important dispersers of such seeds... from swallowing, defecating later>
My second question is, I've also been given another Pangasius catfish. This fish is about 5in in length. I'm very familiar with the requirements of these fish, as I currently house Pangasius from 24in to about 12in in a 2000gal aquaponic res. I wanted to house this fish in a 75gal aquarium, until he puts on some size. His fins looked a little worn, so I wanted to monitor that. Then once healthy, I was planning to release him with the other Pangasius. My only concern is my aquarium(filtered by a HOB Aquaclear 110 and weekly 50% water changes, I probably will add a trickle filter if Pangasius goes in) holds a giant Gourami(female) about 5 inches in length.
Do you think there will be problems with Gourami aggression towards Pangasius. I really appreciate all the great info and keep up the good work. Thanks Brandon
<These two should get along fine together. Bob Fenner>

Question for Bob Fenner. Placing large livestock– 6/24/13
Dear Mr. Fenner,
I've written you/the WWM crew in the past regarding marine aquaria, and I also saw you speak at MACNA in Orlando a few years ago.  I'm actually writing today to ask you more of a "professional question" I'm not sure you'd be able to help me with, but here goes.
I manage a small indoor retail mall in the West Palm Beach, Florida area.
We have a 2,000 gallon freshwater tank that currently houses two very large (approximately 2 ft. each) Pacu.   In the past year or so, we've been experiencing ongoing maintenance issues with the acrylic tank, which is over 20 years old and likely nearing the end of its useful life.  Accordingly, the mall's owner is looking to find a place that might be interested in the two Pacu fishes.  In your travels in the Florida area, would you possibly know any group (public or private) that operates a large freshwater aquarium I might contact to see if they'd be interested in taking these fishes?
<Mmm, well, the best avenue here is for you to list these Colossoma on Craig's List for your area... and to call the local fish stores, maintenance companies, and public aquariums directly re>
 I've already spoken to the aquarium curator at the South Florida Science Center, but they don't have the capacity for fishes this large.
<A swing and a miss. Many folks have too many of these fruit-eating piranha>
Thank you in advance for any suggestions you might have.
Chris Santamaria
<Do try Craig's List... there may well be a large freshwater install near enough, with space. Cheers, Bob Fenner>

Red Bellied Pacu    4/30/11
My Red Bellied Pacu, 4 years old, is gasping for air. Could he have swallowed a pebble? He is always putting them in his mouth.
<... maybe... they do chew the pericarp off of Embryophytes in the wild>
Thank you,
Nancy Mclean
<Likely gasping for air/oxygen. Bob Fenner>

How to find a new home for my Pacu (Bob, I think we need this pasted on billboards around the country!) <<Maybe>>  11/24/10
My name is Robin and I have a 120 gallon fish tank that has become too small for my very large Pacu and 4 silver dollars. I am trying to find them a new home , but I do not know where to search. I would be very
appreciative to try to find them new homes. I have had them for 6 years, but I feel that they need more room than I am able to give them. Any suggestions would really help. I live in Bayville, NJ.
Thank you
<Hello Robin. Yes, 120 gallons is far too small for Pacu; frankly, 1,200 gallons would be too small for them too! Pacu are the textbook example of fish that are only bought by people who haven't done any research. They're insanely large and grow very quickly, so I'm glad you've written to us and that we're able to post this message as a warning to others! Now, how best to find a home for your Pacu? Zoos and public aquaria are your best bets, as these are the places most likely to have a home for such a big fish.
Unfortunately for you, zoos and public aquaria are routinely inundated with adult Red-tail Catfish, Iridescent Sharks, Pacus, Silver Arowanas, and other fish that really have no place in the aquarium hobby. So you may need to write around to such places around the country, not just your local area. Be prepared for the expense of shipping if that's the only way to get your fish to a willing zoo or aquarium. Next, you can ask around the local pet stores. Here in England the chain Maidenhead Aquatics has a policy of
doing their best to rehome fish, and there may be a similarly public spirited store or chain in your country. Thirdly, contact your local fish club. Most big cities have aquarium clubs -- there's a list of American
ones in the back of TFH Magazine for example -- and club members may be able to find you a good home for your fish. Fourthly, there's animal charities. Some of these maintain fish "shelters" and will take unwanted fish from you and find them new homes. Again, there may be some long-distance phone calls and expensive shipping before a solution is forthcoming. Finally, there's euthanasia. With a fish as large a Pacu, you will need veterinarian help to accomplish this humanely. Cheers, Neale.>

Help me please! (Pacu in 37 gallons; death, carnage ensues'¦)   7/17/10
To whom it may concern.
<Hello Spencer,>
I have had my red bellied Pacu for a year now, and he has always been happy. I had him in a 55 gallon tank, but that broke and my parents would not allow me to get anything bigger that a 37 gallon.
<Yikes! I do think you need to take a moment to see how big these fish get.
Have a look here:
Admittedly, that's a different species of Pacu, but it gives you some idea of what to expect. Your species, Colossoma bidens, gets to about 60 cm/24 inches long under aquarium conditions. An adult species will be about 30 cm/12 inches deep. So you're looking at something about the size and weight of a medium-sized dog. Now take a look at your 37 gallon aquarium. There's no way that's going to work in the long term, is it? Minimum, you'd need a 200 gallon aquarium for this species, and realistically 300-500 gallons. It goes without saying that these fish are NOT suitable for most hobbyists, and the lucky specimens get donated to zoos and public aquaria.>
So I was forced to settle with and eclipse 37 gallon integrated tank. When I bought it I properly filled it up an moved my Pacu and two of my cichlids into the tank. Nothing has happened since April, except that I added a very small Plecostomus into the tank.
<Even a Plecostomus needs at least 55 gallons, so I have no idea why you thought adding this species to your 37 gallon tank, together with a Pacu, was a good idea. It's a disaster waiting to happen.>
I just woke up to find one of my cichlids dead,
<Cichlids are very sensitive to poor water quality, and nitrate is an insidious killer where cichlids are concerned. Plus, Pacu are fish-eaters. Sure, they eat fruit in the wild, and nuts too. But they also eat fish. They have very strong teeth. Smaller fish kept with end up dead. In very large public aquaria Pacu are kept with big armoured catfish, but in a 37 gallon aquarium you're just asking for trouble.>
and my pacu's lower lip is swollen, he doesn't really move, and wont eat.
<Needs a new home, immediately.>
Please help me I'm only 15 and me and this fish have become really attached.
<It's nice to hear this, but please understand that affection for your animals has no bearing on their maintenance. Animals couldn't give a hoot about whether you love them; what they need is the right living conditions.
He may be your pet, but he's fundamentally a very large, very difficult to keep animal suited only to either public aquaria or very rich, very advanced hobbyists with indoor ponds.>
For example he eats out of my hand and does a dance each time I see him but shies away from my family.
<Hope this helps. Be sure to tell your parents what the situation is. If you or they need more information, feel free to write back. Cheers, Neale.>

Geophagus jurupari Question, comp. w/ Pacus, hlth, HLLE  3/4/10
Hi Guys,
I have a 55 gallon freshwater tank with 3 Red Belly Pacus and 1 Geophagus jurupari. Upon returning home from a trip I found my Geophagus, 'J.J.' looked as if he had been severely attacked by the Pacus. The fish-sitter had no idea what had happened so I am not entirely sure if J.J. developed some ailment or was simply attacked.
<Could very well have been attacked by these Pacu. Pacu generally should only be trusted with larger companions in very large aquaria. Despite being famed as herbivores, eating all sorts of fruits and seeds, they are opportunistic carnivores too, and will take a bite at anything they think they can catch. They have incredibly strong teeth and jaws. This is a real problem in cramped tanks where the other fish can't stay out of the way. Your tank is FAR TOO SMALL for these fish. The Red Belly Pacu, Piaractus brachypomus, gets to 88 cm/35 inches and weighs up to 25 kilos/55 pounds. These are food fish, and unless you have a 600 gallon tank lined up, there's no way you can properly house three specimens. Do make sure you look at his photo, on Wikipedia:
This is what your fish is going to grow into. To be fair, a typical size in captivity is 60 cm/24 inches, but that's still a mammoth fish almost as deep as it is long, and weighing as much as a dog.>
I had noticed little white spots on J.J. on previous occasions but assumed it was just little Pacu nips but I am extremely concerned now, since one spot, near his nostril, has a large white spot, fuzzy in appearance. The other spots are not as prominent, but the spot covering the nostril is quite alarming.
<These spots, if on the head, are more likely Hole-in-the-Head. This is extremely common when Geophagine cichlids (Eartheaters, like your Satanoperca jurupari) are kept in small tanks. Geophagine cichlids tolerate almost no nitrate, and certainly levels 20 mg/l or higher cause them immense stress. Treatment is with Metronidazole, plus fixing the environment.
Untreated, the fish will eventually die.>
Incidentally, J.J. is eating well and is behaving normally.
<Good, you still have time. Get moving!>
I am not sure if J.J. has developed HITH or has some type of systemic bacterial infection and I am unsure how to treat him.
<See above.>
I am afraid to use anything toxic and was advised to use a 'melaleuca' based medication that added daily to the water
<This is tea-tree oil, and will be of no use against Hole-in-the-Head. The infection can only be treated with Metronidazole. This should also prevent and Finrot following the attack by the Pacu.>
but have seen no results.
<No surprise.>
Please let me know if you have any advice or suggestions.
<Much advice!>
Thank you,
<My pleasure.>
Carol Lyn
<Good luck, Neale.>
Re: Geophagus Jurupari Question 3/4/10

Wow! Thank you very much for the advice and insight.
<Happy to help.>
I had a Pacu in the past, and he was quite entertaining to say the least, but he passed away when he was not entirely huge.
<Oh. Well, there are several species. The Red-Belly Pacu is one of the *really* big ones.>
I was not aware of quite how large these guys will get- I will DEFINITELY re-think my aquarium. Thank you for that advice.
<No problems.>
Thank you also for advice on J.J. I will head to the pet supply store for the Metronidazole and will definitely test the nitrates.
<Very good.>
Thank you very much; I appreciate your help.
Carol Lyn
<Cheers, Neale.>

Pacu sick    1/15/10
My Pacu is 10 years old and is getting a long awaited tank but she suddenly is bloated.
My 2year old threw a brazil nut shell and all in the tank at Christmas and before I could get it out Pacu bit it in half and ate some.
<Shouldn't be a problem. In the wild, they eat nuts, shells and all.>
Here we are 3 weeks later and she had a distended abdomen and she has on either side of tail a fuzzy white spot. near the anal fin.
<Likely unrelated. The white fuzzy spots are more likely fungus or Finrot, and should be treated accordingly. These are almost always caused by water quality issues. Since Pacu are simply gigantic fish, it's very easy to expose them to poor water quality.>
Can she digest nut shells?
<They don't digest them, but they are able to crush them, and if they swallow any fragments, they should pass out the other end.>
I tried to feed her peas no go and a treat of brine shrimp was no good .
<Don't feed for a while, and by all means add Epsom salt to the water (1-2 tablespoons per 10 US gallons). Epsom salt relaxes the muscles of the gut, allowing blockages to pass out more easily. If a fish is bloated, this can
often help.>
I want to switch her into larger tank but I am afraid the stress might be worse.
<How big is the current tank? How big the new tank? These would be factors in my decision here.>
Water tests perfect but a 20 in nitrates guy said it would not be dangerous for fish.
<In theory, 20 mg/l nitrates should be non-toxic for these fish. But I'd do a good sized water change (25-50%) anyway, before adding the Epsom salt.>
What should I do?
Amber same tank and set up for 5 years now
<Must be a pretty big fish!>
she is strict vegan
<Which isn't correct. Pacu are omnivores. Indeed, one could stretch a point and state that all fish in the Piranha subfamily (Serrasalminae) are omnivores, and what differs among them is the ration of meat to plant foods. In the case of predatory Piranhas, these fish mostly eat meaty foods but take seeds and fruits at certain times of the year. In the case of the Pacu and Silver Dollars, plant foods predominate, but insect larvae, zooplankton, snails and small fish will be eaten should they become available. The problem with strictly vegan diets is that these can very easily be vitamin deficient. They aren't terribly easy to get right for humans, about which we know a lot in terms if nutritional requirements, and I'd argue practically impossible to get right for fish, about which we know far less. So a good diet might well be 70% plant foods, but the other 30% should include a good quality pellet food, shrimps, chopped white fish, and other protein and especially fat rich food sources (fats containing vitamins that plant foods often lack).>
Maui bloat?
<Do you mean Malawi Bloat? This is a syndrome observed among cichlids from Lake Malawi when aquarists keep them in tanks with the wrong water chemistry. Often, the addition of sodium chloride (salt) to the water is
the triggering issue. It's to do with osmoregulation. Anyway, I don't think it is relevant here. Cheers, Neale.>

Re: Pacu tank sizes   1/16/10
Sadly her tank currently in is only 50 gallons approx 4 feet wide by 1 foot wide
<Far too small.>
and until about a year ago the tank was perfect but in increase in feeding a wide diet from deshelled almonds which she loves (raw) and a varied diet of carrots (she munches baby carrots), grapes, cherries lots of oranges, tangerines,
<Would be VERY careful with acidic foods; they do tend to cause stomach upsets in many animals, so use very sparingly.>
cucumbers, zucchini, bell peppers (red), radishes, apples, and occasional romaine or spinach.
she does not like any stone fruit (apricots, peaches, etc..)
Had apparently caused a huge growth spurt which was noticed by everyone within that year.
<Well, she needs whatever food you give her. These are incredibly fast-growing fish that reach huge sizes. We're talking the size/weight of a German Shepherd dog. So yes, they need a lot of food.>
My husband was known for giving her the Royal Canin dog and cat food on occasion which caused large defecation, clouding the tank and making us change water more often (we actually never saw a bowel movement until then) we assumed she just never did till dark I guess.
<Meat from mammals and birds is very bad for most fish. The oils in warm blooded animals become solid fats in cold blooded animals, and these can cause blockages. So as/when you feed meaty foods, offer fish, seafood,
earthworms, insects, etc.>
She also loves algae discs (like potato chips)!!
<Algae wafers are good.>
I never paid true attention to her specific needs until she out lived everything in the original tank she used to be the size of a half dollar (coin).
She is not aggressive but did kill a 10 inch Pleco older than her (Pleco often poked her with dorsal fins to get algae discs).<Not sure it was aggression or because the Plec poked her. Pacu ARE predatory, and the WILL catch, kill smaller fish. It is their nature to do so.>
So she is alone in the tank now and we have gotten a 120 gallon 5ft by 18inch by 24 inch tall tank. we will not be adding anything-she ate both previous snails both as old as her and size of tangerine.
<Yes, snails are part of their diet too.>
She has a great personality and she is rather calm for everyone else freaking out about the bloat.
When she is in distress she breaths hard and swims frantically often slamming into the sides, looking overall panicked. (very scary)
Currently she is quite calm.
She will not eat anything I tried peas yesterday and she refused to eat them.
<Then don't feed her until she's in the new tank. She can go a week or two without food, no problem.>
She is large approx 18 inches tip to tip, almost a foot dorsal to ventral.
<In a 50 gallon tank!!! Seriously, HERE'S your problem.>
I know the tank we got is still considered small but for right now it should be better than what she is in.
<Needs more than 50 gallons.>
I plan to cycle the water with her filter for a few days, before I put her in there.
<I would move the mature filter and the fish to the bigger tank all at the same time. Assuming the water chemistry and water temperature of the new tank is the same as the old tank, disconnecting the mature filter and reconnecting it within a few minutes shouldn't harm the filter bacteria.
Leave the mature filter running on this tank for at least 6 weeks, alongside whatever new filters you're installing. Bacteria will colonise the new filters, and after 6 weeks you can, if you want, remove the mature filter.>
Should I add the Epsom salt to the new tank too and keep it in there on a regular basis?
<No. Just for a few weeks, while treating for bloating and/or constipation.>
I put rock salt in tank yesterday afternoon and the white fuzzy stuff is almost gone-left the light on and got temp up to 78 degrees F( was 74) I put approx 4 table spoons for the entire 50 gallons.
<Rock salt will have little/no benefit here. It isn't what you need. And seriously, 4 tablespoons in 50 gallons is about as impactful as a ball of spit in the Atlantic Ocean.>
Temp usually stays between 76&78 F. Will temp increase to 78 increase digestion?
I have no heater cause they freak her out and no aeration because she eats the air line and chews on the stone, or air rod(metal or not), even tried to eat the large clam with the pearl(typical tank decor with intermittent bubbles),
<You do need a heater unless the water NEVER drops below 24 C/75 F. Even relatively short duration chills can stress tropical fish, and expose to cool water for more than a day will often weaken them severely.>
she flipped it upside down and chewed through the line right in front of me.
<Then use an external heater. I happen to like the Hydor ETH "inline heaters", which you slot into the outgoing water hose from an external canister filter.>
If it scares her it gets broken or has to be removed.
She had a stripped tank for the last three months cause she was slamming into things and hurting herself (hopefully larger tank will help)
<I will. But bear in mind these are migratory, riverine fish used to swimming long distances.>
I do not like using goldfish for cycling could I use guppies I have approx 50 currently, or will her filter work just as well?
<See above.>
Here are the water readings done at local fish store(until recently I never tested my water, and I have had tanks for 15+ years.)
When I try the transfer I will test first are there ideal settings for her particularly?
<0 ammonia, 0 nitrite, pH 7-8, hardness around 10-15 degrees dH. Although wild fish come from soft, acidic water you don't want this in captivity.
Soft water is prone to pH instability where big fish are kept, and acidic water inhibits biological filtration. So basic, moderately hard water is the ideal.>
<Here's one source of problems. Ammonia above zero is toxic.>
Salinity: N/A
The internet tends to not have much info on care just on what freaks of nature they are for at home tanks, and how people use them for sport fishing.
<Indeed. These are food fish. Not pets. You're keeping the fish equivalent of a sheep.>
What specific diseases should I stay prepared for, what would be good things to keep on hand.
<Actually, these fish are very hardy. Just difficult to house.>
She has never been sick(disease) before.
<Good to know.>
Thank you for all your help.
<My pleasure.>
Amber & Pac ( Pacu )
<Cheers, Neale.>

Pacu in Quarantine 05/25/09
Hello Crew--
I have a quick question for you. My husband and I recently completed our 1000 gallon indoor pond for Guido, our red-tailed catfish.
<Ahh! I recall>
WWM has been instrumental in getting me through this trying experience, and I thank you for it. The pond is complete, and 18-inch Guido is in it (now looking very, very small...). We purchased a Pacu, who is about 14 inches, to be Guido's only tankmate. The Pacu was in a pond at our LFS, and was a really good-looking fish, without any of the scars typically found on Pacus of his size. He is in Guido's old tank, alone, for quarantine. It is 125 gallons. However, the water quality is decreasing (I think I'm overstocked hehe) and I'm beginning to wonder if it wouldn't be better to put him in the pond.
<Very likely so... not much reason for quarantine for an animal that has likely been tank-raised>
We have a four-day vacation coming up, and my mom, who is caring for the fish, won't be able to do water changes should problems occur. My worries re moving the Pacu to the pond are the following: 1. That the Pacu would cause an ammonia spike in the pond, as Guido has only been in there a couple of days, with no spike evident yet. I'm not sure if we'll see a huge spike, due to the water volume and decreased feeding.
<What did you do... will you do to speed up the establishment of nitrification? I'd carefully pre-measure foods to be left for your mum to use>
2. That the Pacu is ill, though he was in the pond at the LFS for at least a month, and does not appear to be sick. I know quarantine is always best, but in this situation, I'm worried the quarantine itself will make him sick. What is your opinion?
<I'd move this fish>
I appreciate your help, and want to do right by this monster fish. It's so weird with him in the tank, which is at the foot of our bed. I haven't gotten over the feeling that there's a stranger in the room. Again, thank you for what you do for fish and their owners.
<Welcome Melinda. Bob Fenner>

Re: Pacu in Quarantine 05/27/09
Hi Bob--
Thank you for your reply. I was leaning in that direction also, but it's nice to be able to get a second opinion from a trustworthy source.
<Ah yes>
In anticipation of stocking our 180 gallon saltwater tank (moving up from a 75), I recently purchased "The Conscientious Marine Aquarist." The book is informative and your conversational tone makes it easy to read.
<I appreciate your input>
The photographs are also very nice. I will move Mr. Pacu as soon as hubby wakes up -- ahh, the joys of moving fish that are the size of house cats!
<Mmm, yes... best done with a heavy duty (fish) bag... 4 ml.s... scooping up, with minimal water... and lifting (watch your back/s!)...>
As for your question re the nitrification process in the pond, we have added two types of bacteria-in-a-jug -- one that is Dr. Foster and Smith brand, and one recommended to us by our local pond store. We tried to cycle with ammonia, but after a month passed and nothing happened (i.e. ammonia stayed, nothing else appeared),
<It is often the case that exogenous ammonia does this... poisons the system...>
decided that it would be better to just do water changes if needed. Thank you again for your help and all you do.
<And you for your participation as well. BobF>

Oscar's tail (entire tail) eaten off, help!  5-10-09
I'm in a bit of a hurry (as I'm sure you'll understand why, as you read on), so I apologize in advance if this information is already posted on your site.
<Likely is written elsewhere, and you would actually get a reply more rapidly using the Search box...>
Our Oscar and Pacu have been tankmates since they were babies, together for over a year now. They'd been best buddies, with only the occasional bullying by the Pacu. Well, it finally happened, 2 nights ago we caught the Pacu eating the Oscar.
<Pacu are omnivores with a taste for fruit, but I'm sure they'll bite small, sick, weak or moribund fish. So while they're fairly trustworthy fish kept alongside tankmates of similar size, if this Oscar was substantially smaller than the Pacu, or for some reason weakened, then that might explain what's happened here.>
Fins are nearly completely gone, tail IS entirely eaten away (into the fleshy part). I'm going to attach a photo. Naturally, we moved it into a QT tank, doing water changes daily. Didn't think Oscar was going to even make it through that first hour, now here we are, 2 days later and he's figured out how to swim normally again, ate last night, poo'd just fine! My main question (and reason for writing) is...will adding aquarium salt reduce the risk of infection/fungus?
Will it also aid in the healing process?
I intend to add some tonight, just because I know that it does help, I'm just not sure how, haha.
<The idea salt is a cure-all is an old one, but it really isn't much good.
For one thing, marine fish get bacterial infections, and they're in seawater! This Oscar is in seriously bad shape. You need a robust, aggressive treatment here that deals with both Fungal and Bacterial infections, since your Oscar WILL get both if not promptly treated. I'd be looking at Seachem PolyGuard, Seachem NeoPlex, eSHa 2000 or similar.
Obviously NOT something like Melafix, which is, at best, a preventative tonic. A proper antibiotic such as Maracyn would be a very sensible augment to the treatment, especially if the tissue remained red and sore for more than a week or so.>
Will the tail grow back, or will our little Oscar just be tail-less for the rest of it's life (if it continues to survive and do well)?
<Given time, fish show an amazing ability to regenerate fins. It all depends how much of the bone on tip of the caudal peduncle (the muscular "stem" of the tail) has been damaged. If the peduncle is basically sound
and the bones intact, with luck, this fish could regrow its fins.>
Thank you in advance for ANY information you can give me. It's MUCH appreciated.
<Cheers, Neale.>

Re: Oscar's tail (entire tail) eaten off, help!  5-10-09
"Pacu are omnivores with a taste for fruit, but I'm sure they'll bite small, sick, weak or moribund fish. So while they're fairly trustworthy fish kept alongside tankmates of similar size, if this Oscar was substantially smaller than the Pacu, or for some reason weakened, then that might explain what's happened here."
Not this little bastard, I've learned there's nothing trustworthy about him! :) While the fish is incredibly loving and docile with me (insists upon being pet during water changes and such), it will eat anything in the tank simply because it can catch it.
<Ah, I see. Does happen, as I said. The idea Pacu are pure herbivores is widely quoted by erroneous; do also be careful when petting your Pacu: they are confirmed "biters" and have extremely strong teeth and jaws evolved for crushing nuts. Your fingertips will be as nothing in comparison!>
Tis a naughty little fishie. I really should have known better, however since the O is just over half the size of Pacu and they'd been together so long, I made the simple mistake of believing they were fine together.
Lesson learned.
<The hard way...>
I'm not sure why it prefers "meat" over "fruit", maybe because it's THE DEVIL??
<They're omnivores, as I said, and view both as food, much as we do. While Pacu are generally very good choices for robust communities alongside Red-tail Catfish and the like, clearly combining them with smaller Oscars isn't reliable.>
Also, we will treat the Oscar, I can't tell you how much we appreciate the advice on medication. While the Oscar is in bad shape, I'm quite surprised at how much fight this little thing has in it! Maybe it's because my 5 year old sits at the QT tank all day chanting "Fight, fight, fight". Hehe :)
<Hmm... is she chanting for a rematch, or simply hoping the Oscar lives to fight another day?>
I'll be bookmarking this site, I'm very happy with the quick response and such detailed, helpful information. You're amazing :)
<Thanks for the kind words. Cheers, Neale.>

Pacu's in trouble (RMF, any ideas?), hlth., sys.  4/7/09
I have 2 red bellied Pacu's.
Very healthy prior to their present deteriorating condition.
<Everyone is healthy until they get sick, so this doesn't really mean much.>
Approx 4 inches long in a 40 gallon vertical tank.
<Not a chance of maintaining this species in a tank this size. Not a single sliver of a chance. A "vertical" tank is a bad choice even for guppies, since it has a poor surface area to volume ratio. Any book would tell you
this. While "tall" tanks may look nice, they're essentially useless for keeping fish. Please be careful when shopping to buy stuff that works rather than what appeals to whimsy.>
I did a water change and clean approx 1 1/2 weeks ago. Removed 3/4 of the water. I now understand that I removed too much.
<Hardly likely to make them ill. Just to clarify: provided pH, water chemistry and temperature remain roughly the same, you can change as much water as you want. Think about what happens in the wild; do fish sit in tanks of water? Nope; they're constantly swimming through water that flows past them.>
The water is crystal clear. My other small fish in the tank are fine, just the Pacu's are failing.
<Because they can't be kept in a tank this size. Pacu are gigantic, the size of dogs when mature. They probably displace about 40 gallons! They're classic riverine fish with a need for the oxygen and circulation only a big tank can provide. Colossoma macropomum is a superb food fish, but an appalling aquarium fish.>
They continued to look healthy after the change, then apparently went into a mating/spawning frenzy. It is quite beautiful the spiral dance, but they are now looking hammered and their color looks pale. Numerous nicks and their mouths are cut.
<Doubt they're spawning unless they're mature, i.e., about 60+ cm in length.><<Heeee!>>
They will not eat and it has been at least a week and a half since they took a pellet. Wondering if they mate to the death and that I will wake up to them belly up?
<If they do die, nothing to do with spawning.>
Their dorsal fins don't stand up and they are confined to one corner of the tank now. I don't see any eggs. Not sure what to do. Water temp is 82.
<Too warm.>
Hope you can advise me on what steps to take. Steve
<First thing, if you want to keep Pacu, you're going to need a tank around ten times the size. I'm not kidding. I can't for the life of me think why you bought them. Would be like shopping for a hamster and bringing home an elephant. Seriously, these are big, extremely difficult to maintain fish.
Most aquarium specimens die prematurely, but those that don't get to around 80-90 cm in length. While I have no idea what the specific problem with these fish might be, it's surely environment-related, so the "cure" would involve moving them to suitable conditions, hoping that they'd improve.
Good luck, Neale.><<I do concur. The environment is at fault here... RMF>>
Thanks Neal. Steve
<Happy to help, Neale.>

Fish Question, Pacu hlth., sys.   6/4/08 I have a very serious question that I would love to have answered. There are no vets in my area that will deal with fish, so I am helpless. I have a 120 gallon tank and in it I have 2 Pacu's, one Jack Dempsey, and 2 Pleco's. My Pacu's are about a foot long and very large. <... about a third of possible length...> Well, today I just noticed a huge mound of something looking like intestines, coming out of my biggest Pacu. It looks as if he has a split, perfect like done with a razor, on his bottom, right in the general area where he passes bowel movements. It is not stringy like poop, but it is large, like the length and width of a grown mans thumb. He/she is eating and swimming as if nothing is wrong. Could he have somehow split open there and it be his intestines coming out? <Mmm, yes...> And if so, what exactly should I do other than wait and see if he survives or is there anything at all I can do? <Well... best to look for larger quarters, remove any sharp rock, other objects that might have contributed here> If it would help more for me to take a picture of him and send it, then I will gladly do so. Thank you for any help you can give me at all. Deborah Masterson <The Colossoma need much more room... a lack of exercise (loss of tone in muscle) has likely contributed to the tearing, prolapse here. Bob Fenner>

120 for Pacu Hi Bob, I love to see all the questions and answers on the site. One of my tanks is a standard 55 gallon freshwater tank. While most of the fish in the tank seem pretty comfy with the size of the tank, I do have two monsters that have out grown it. One is a silver Pacu who is about 12" long (big enough to fillet or walk on a leash) and an algae eater who is 14" long. I want to build a bigger tank for them to roam in. I was thinking about a 120 gallon acrylic tank. <The Pacu will quickly outgrow this, too. These are true monsters getting over three feet long.> What are you thoughts on this. Also, what would be the critical info on building a tank of this size (length, width, height, thickness...). I'm sure you know what I am asking. Any and all info you can give me as well as links to other sites would be greatly appreciated. <Do take a look through the FAQ on building tanks here http://www.wetwebmedia.com/diytksfaqs.htm> Thanks, Marcelo <You are welcome. -Steven Pro>

Piranhas and Pacu (Oh! MY) Robert: <Anthony Calfo in your service... Bob has superglued himself to a piece of coral...strike one on his first foray into coral propagation> Thought I would give you an update and ask you a few more questions, if you don't mind. It's been over 6 weeks since I've had the tank set up and the Piranhas are doing fine - despite the fact that I have yet to get the pH down to their ideal range: 6.5 - 7.0 The tank has reverse osmosis water in it so it's very soft (85 ppm) so I would think that the pH would adjust fairly easily, yet it won't go below 7.6!  <what is the total hardness of the water coming out of the R/O unit and has this number been confirmed with another brand of test kit?> It's a mystery to me why the pH won't budge.  <85ppm is soft...but not extremely soft assuming that the test kit is accurate and not reading a bit low (which could explain the resistance)> The tank has been up for a while now and according to what I've read, all established tanks will see a decrease in the pH levels as this is a natural process.  <agreed and inevitable for most> I've also read that the softer the water, the less buffering and therefore the easier it is to adjust pH levels.  <yes> Maybe 6 weeks isn't long enough and maybe 85 ppm is still too hard of water. Any ideas on what's going on? <you are correct on both counts...but don't be obsessed with the low pH and soft water unless you are trying to breed them. The other side of the coin is that very soft and very acidic water is VERY unstable and quite frankly dangerous with the slightest slip in husbandry (overfeeding, delayed water change, etc)> I'm going to be setting up an 125 gallon soon and will have a Pacu in that tank.  <the tank is still not big enough...quite frankly, I hope that you don't buy the fish. It's an inappropriate animal for most tanks growing to over two feet in length. Cruel to let it stunt and die prematurely (a few years old) as most do> My research indicates they like the pH levels even lower: 4.8 - 6.5! <too dangerous for captive aquariology unless you are research strict about maintenance> If I can't even get my 55 gallon to a neutral pH...how am I possibly going to get an 125 gallon to a pH level of 4.8 - 6.5 ??? <my friend, have you considered drinking alcohol? Relax, goombah. A pH around neutral is safe and reasonable for such hardy fish and will serve you well considering the waste load they produce and potential for disaster at low pH/unstable soft water. If you are willing to go to such great lengths for water quality... breed wild caught discus instead and at least make money for your pains...hehe. Kindly, Anthony> Travis  

Follow-up to Piranhas and Pacus Oh My! Anthony: <You got Steven pulling his shift answering some of the daily mail.> Thanks for your input...I appreciate it! Can you tell I'm just a tad on the obsessive compulsive side? he he I'm glad to hear that I don't need to be so worried about the pH levels and can relax a little. I do have a couple follow up questions on the Pacu. Don't these fish grow to the size of the tank? From what you're telling me they'll just grow and grow and grow until they basically die (if the tank is too small). <It is not quite true that fish grow to the size of their tanks. Freshwater fish are a little easier to stunt their growth, but that is not healthy at all. How would you like to live your whole life in your closet? Get the picture.> How big of a tank do you need for a Pacu? <For any large fish, find the maximum length. The tank's width should be twice the maximum length of the fish and the tank's length should be four times the maximum length of the fish. And remember that this is a minimum. For a Pacu, 4 foot wide and 8 foot long and probably 2 or more feet deep.> I'm not necessarily "married" to the idea of getting one so I'm open to alternatives. Can you think of any? The Pacu is the exact kind of fish I'm looking for: a freshwater fish, grows very fast, grows very big and won't attack you if you put your arm in the tank! I've tried Oscars in the past but had terrible luck with them as they always got some kind of disease (ich, hole-in-the-head, etc.). I can't think of any fast growing, large freshwater fish other than Pacus and Oscars so that's why I thought I would consider a Pacu. Any suggestions? Travis <Generally, Oscars are a great fish as long as you keep their water clean with frequent, large water changes and good filtration, house them in an appropriate sized tank, and feed them a varied diet (no feeder fish). There are many other cichlids that meet you request, but they all have the same captive care requirements as above. Kind regards, Steven Pro>

What's in a name.... I am interested in Parrot Pacus, the trouble is that there is not a lot of info on the web, could you give me some? For example, what is the minimum tank size for two or three of them, how easy are they to care for, and where can I find them? --Aaron <Hi, Aaron!  First off, by 'parrot' Pacu, do you mean Ossubtus xinguense?  Fishbase.org says they max out at about seven inches, so *if* you can find them, you could probably keep a few comfortably in a 40 or 55 gallon aquarium, though as always, larger is better.  As for ease of care - well, like you, I'm having a great deal of difficulty finding information on this fish.  I'll refer you to WWM's piranha/Pacu/silver dollar information: http://www.wetwebmedia.com/FWSubWebIndex/serrasalminae1.htm .  And now, for finding them.  This is going to be the tough part.  Do a Google search on the scientific name, and also get in touch with some of the companies that deal with south American fishes (I can only think of www.belowwater.com off the top of my head, but I know there are plenty of others).  I believe you'll have some real difficulty trying to find this Rio Xingu native.  I think if you do find them, they'll come with a hefty price tag.  But looking at the FishBase pic, that is indeed a cute fish.  -Sabrina>

MEANWHILE MEET THE PIRANHA THAT MURDERS FRUIT 11:00 - 01 September 2003 Piranhas have a reputation as deadly and ruthless predators, capable of stripping a carcass to the bone within minutes. But yesterday scientists revealed how a newly-discovered relative of the sinister species has developed a distinctly sweet tooth, enjoying chomping on fruit. The fish is one of a range of bizarre and colourful marine creatures revealed to the world for the first time this weekend. A team working in the rainforests of Venezuela have identified 10 previously unknown species of fish, along with a new breed of shrimp. One of the new additions, an armoured catfish complete with a crown of protective spikes, was immediately dubbed "punk". The team, US-based Conservation International, has also identified a new relative of the Bloodfin Tetra family, a vivid red and green fish named Aphyocharax yekwanae in honour of the native Indians who live in the area where they were found. The discoveries were made in the Caura River Basin, around 300 miles south east of Caracas, an area of untouched tropical jungle crisscrossed by waterways. Conservation International is now calling on the Venezuelan Government to make the 11,115-acre area a wildlife reserve. Zoologist Antonio Machado said: "For its size, it's incredible what the area has. It's a hot spot that should be protected." Conservationists fear the tranquility of the river basin will be shattered by human settlement, increased farming and fishing. They also claim it is at risk from a planned hydroelectricity project. <Again, thanks to you Mike. Bob F>

Pacu Snout Sore Hi guys, <Hi, Andrew, Sabrina with you today> How's it going? <Not bad at all, thanks!> I have a six foot tank housing 2 juvenile Pacus and one small black shark.  The larger of the 2 Pacus has some injury around it's snout area, it looks similar to hole in the head but I don't know exactly what is wrong with the fish.  He is feeding well and actively swimming around the tank, plus he is exhibiting remarkable growth.  I am concerned about his snout though.  I bought him at the shop having inspected the injury, which seemed minor at the time.   <Minor or not, it's always best to try to get only healthy, uninjured fish, as I'm sure you now know> Do you know what is affecting his snout ? <Well, with the pics you sent, it does indeed look like hole-in-the-head/HLLE.  This illness typically affects large predators (usually cichlids) and can be brought about or exacerbated by constant poor environmental conditions or sometimes improper feeding.  It can be a protozoan infection (Hexamita) and may also be worsened by systemic bacterial infection on top of that.> How should I go about treating him ? <Well, first off, absolutely keep his conditions pristine, for starters.  Good water quality is a must.  Moreover, I'd recommend to put him in a hospital tank for treatment with Metronidazole, which does seem to have some effect on this illness.  His face does look pretty bad; he may never heal completely, even if you can kick the problem.  Hopefully, though, you can at least get it to stop progressing, which will surely kill him eventually. I suspect maintaining a healthy environment and letting time go by will be your best advice, yet I would appreciate your opinion as the snout looks quite serious - the flesh is exposed to the extent that the top dentition is clearly visible.  I enclose some pictures to assist your speculation. <Definitely good advice to keep his environment healthy ;)  but in his case, I do recommend treating in a hospital tank.  It does look quite serious at this point.> Thanks for your time in advance,  Andrew Hough <Any time!>

Pacu I have a red belly Pacu that is lodging in a 55 gallon tank. <Just so you know, the Pacu will out grow that 55 gallon tank.  They get very big.> I transferred him from a 30 gallon tank a week ago--my question is--why does he seem afraid of the florescent light compared to the light that was provided by the typical pet store hood for the 30 gallon tank? <Pacus really don't like bright lights, but the real problem is that it's just getting used to it's new home.  Try not to keep the lights for a few days... allow it some time to get used to it's new tank.  Then once it's seem to get accustomed and less flighty then you can turn the lights on more.  Just give it some time and it should be back to normal.> he stays at the corner of the tank until the light is turned off--then he swims around--once I put the light back on he swims erratically hitting the sides of the tank and acts afraid the whole time the light is on--should I put a light filter on to change the color of the bulb?? <If you want to change to a lower watt bulb that might help it.  But, I really think that the problem is that the fish is just adjusting to it's new environment... give it some time and it should be fine. -Magnus>

Pacu Hey WetWebMedia guys, I got Pacu in his new 90 gallon! Boy was that an experience, it was weird, he didn't move a muscle until he was in the water in the new tank and then all hell broke loose, he even got caught in the net! <Yikes... I've been present at the move of many a Colossoma... better NOT to net them, but instead direct into large, thick plastic bags, drain off most of the water, and pick them out one at a time this way> Fortunately no blood was lost, just some really split fins which I'm using wide spectrum antibiotics to help. So now, I just have a pouting Pacu that wont eat much, I'm sure he'll eat more in a couple days. <Agreed> So here's my question, all of the fish that I moved into the new tank (Pacu, Pleco, Jack Dempsey, weather loach, and Pacu's pet Charlie (The Gourami that likes to school with Pacu @_@)) all don't like to have the light on, they don't do anything at all. But if I have the light off with other lights on in the room its like a party in there. All I have is a 48 inch single tube fluorescent light fixture and I'm wondering what the best light would be for night time viewing. <Mmm, what ever suits you, the human/s... best to put whatever lighting you use on a timer though... to keep the cycle consistent> I'm not looking for anything expensive, just like maybe a hardware store black light for instance. Any suggestions? Thanks. <Bob Fenner>

Re: Pacu lighting ok, as long as the black light doesn't mess up their colors or anything, but perhaps I won't use one and just find something a little softer. Not sure yet. What was really hard about the move though, is he's 19 inches long and 20lbs easy, <Yes... have seen C. macropomum in captivity near thirty inches in length> I didn't think that a plastic bag would be right, could rip even. <You are wise here... I'd double or triple bag... with 4 mil bags... and have two or more friends to help lift out of the tank> Unless you guys have something special that you would use? Perhaps a tarp sling between two plastic pipes that is closed on the ends? That way you could coax him under it and lift it up around his sides and close the pipes together. I'd like to know for future use. Thanks! <Not anything that might scrape these fishes... they have very fine scales and soft fins that are easily damaged... as you know. Some public aquariums use anesthetics in moving these Serrasalmines and other large, strong specimens. Bob Fenner>

Re: Pacu moving Ok, I don't know where I would get any anesthetics and that could be dangerous (cardiac arrest or what ever) so next time I'll try the 4 mil bags, but maybe more like six. Lots of thanks!!!! Pacus are great pets, a little jumpy, but mine is friendly enough to eat out of my hands and let me scratch his sides with the cleaning tubes from time to time, he's a real great pet! Sometimes I get a little nervous that he may erupt the tanks, so when I'm not home I actually cover the front of the tank with a blanket Thanks again!!!! <Thank you for this. They can indeed be gentle giants of wit and grace. Bob Fenner>

Hey guys, my Silver Dollars are mating. I don't know if you remember, but a couple of months ago I had questions about diseases that were in an  80 gallon tank that included a very large Red Belly Pacu (pic. included) four silver dollars, a couple Balas, a Jack Dempsey, a Large Gourami, some Corys and  a very large Pleco. Now I know this is bad to have all these fish in this tank and it's really crowded. But somebody had to adopt these fish from the family that wasn't taking care of them. They were riddled with Ick, fin rot, and hole in the head disease and they also didn't have adequate filtration ( a pitiful old Penguin 300 that looked like it hadn't been cleaned or changed in months) But I've added a Magnum 350 pro kit with a Turbo Twist UV Sterilizer which is taking care of all the Ick and fin rot beautifully. Also, a couple days ago I picked up a used 90 gallon tank with every thing I need except the adequate filtration for $150, although this time there's no fish in it When all this first started, the Silver Dollars were in the worst shape, I thought they would surely die. But I've nursed them back to the point where their mating! Believe it or not, these people just happened to have one male and three female in there, and they decided to mate right in front of my Grandparents during thanksgiving dinner. That was really embarrassing let me tell ya.          So my question is: how can a set up a breeder tank for these larger fish (6 inches long) so that when they are ready to lay the eggs the eggs are protected. Also, how does this work with Silver Dollars? I've successfully bred over forty sword tails in three batches now, but I've never bred an egg laying species. Please help! < Silver dollars are egg scatters as are most characins. The male and female do a little dance and will swim side by side. As they do this the female releases the eggs while the male fertilizes them. The eggs drop all over the bottom of the tank and ornaments. They are quickly eaten if they are not removed. The key is to set up a tank that is big enough for them to spawn by you need to keep them separated from the eggs. Go to the hardware store and get some lighting panels that resemble egg crates. Cut them to fit your tank and suspend them off the bottom. Next time the fish spawn the eggs should drop below the egg crate where the fish cannot get them. ^Then remove the adults. Another method would be to cover the bottom of the tank with glass marbles. The eggs would fall between the pore spaces between the marbles. They prefer to spawn over tuffs of plants some java moss or an artificial spawning mop would help. The eggs are very susceptible to fungus so the tank must be kept clean. Water temperature hardness and pH are all critical to get a successful hatch. Water should be clean, warm , soft and acidic for the best results. When the fry become free swimming they can be fed. depending on what species you have the adults may not eat the fry. They should be fed infusorians until they get big enough to eat baby brine shrimp and crushed flake food. Females will be plumper than the males. Some species do not eat the fry at all! Breeding these fish is not that common . Good luck.-Chuck>   

Freshwater Tank and Pacu Hey Guys, I found your site a few days ago and I can't stop reading it!!! Thanks for all your support!!! It is informative as well as confusing, and I mean that in a good way as in making you think and raise questions. So I hope you don't mind answering a few of mine. A little background as to where my questions lead. About 2 years ago I set-up a fresh water 55 gallon tank in a dialysis facility where I work for the patients, which they enjoy. The fish that were donated at the time included a Pacu. I knew eventually I would have to transplant her into a larger tank. Since then the other fish have been removed and placed into other tanks. Recently, the facility was donated a 265 gallon tank, stand and some accessories which I am now preparing to put our larger Pacu in alone. The tank came with 2 magnum 350's but in research I discovered that the combined flow rate of these pumps would not turn the water over the enough per hour, plus the pumps are only are mechanical and chemical filtration. So I am building a wet/dry from scratch with a little giant TE-5. I estimate should turn the water over about 1200 gph, to augment the magnum 350's. Is this over kill? Can you have to much turn over per hour? <No.> Will this also be too much turbulent return flow for a Pacu? < Pacus come from the Amazon and can handle a pretty good water flow.> She is about 10 inches in length now. If it is, can I just incorporate the mechanical and chemical filtration into the wet/dry and ditch the magnums? < You can just use the wet/dry but I always use a second system as a backup.> Ok, next bunch question is in regards to nitrate and bio-balls. I am having difficulty determine the amount of square footage of bio-balls that I would need. Do you have a formula in relation to tank size or a recommendation? I am also reading that bio-balls are being removed once nitrate levels begin to rise when approaching the recommended maximum levels. Do you remove them a little at a time until you reach appropriate or equilibrated conditions that coincide with regular water changes?? Am I totally on the wrong track and confusing this with marine aquariums?!?! < Too many variables. How many fish? How big are the fish? How often are you going to do water changes? The problem with building these big massive filters is that while they remove the waste from the tank, the fish waste is actually still in the system and needs to be removed. If you only clean it once a month because the water flow is not restricted then you still have a lot of fish waste that is generating lots of nitrates. You still need to service the filter regularly to get the nitrates down or the water changes will drive you crazy. Reducing the bio-balls does nothing to reduce the nitrate content unless they are so loaded with junk themselves that they become the source of the nitrates.> Ok last bunch I promise. How to acclimate, my Pacu to the new tank. Being I work in dialysis and water treatment, I have access to RO water polished by DI, post UV and Ultra filters with a carbon, multimedia, and softener pretreatment. So since the water I will be using will be for the most part is inert, I was planning on cycling the water between the two tanks with a pump at a rate of about 2-3 gallons per day for about two weeks. Then gradually increase the rate to about 100 gallons an hour over the next week till the tanks equilibrate themselves in pH, hardness, nitrates, temp. Yes, No, Maybe??? Any other conditions to avoid stress and shock to our mascot I should be concerned with? < If the Pacu is currently in tap water then set up the new tank with the same matching tap water. You have had him for two years so  then you can match up the water to what he is in now. Using "pure" water without a buffer can lead to dangerous consequences.-Chuck> Thanks guys, I have never set-up anything this size before or transplanted a living being of this size. Failure is not an option!!! This will help me in a couple of years to transplant our Pacu again into a larger tank which I know she will eventually need. All your comments, concerns and criticisms will be greatly appreciated. Humbly, John Mahalko

Bend Over so I can Take your Temperature What temperature does an outdoor water pond need to be for a Pacus freshwater piranha??  They have wintered in a indoor tank and were in the pond the past summer.  < These fish are from the Amazon River and I would recommend that the lowest nighttime water temperature be no lower that 75 degrees F. Any lower than that and they could come down with ich and be difficult and expensive to treat. -Chuck>  Kathy

Red Bellied Pacu  3/16/04 <Hi, Pufferpunk here tonight> I have two red bellied Pacu.  They are about a year old or so, and are roughly 8 to 10 inches, a pretty good size.  Up until today, haven't had a bit of problem with them.   I turned the light on, and noticed that one of the Pacu, for lack of a better description, almost albino like or turning kind of milky white.  They've both been growing nice, very active and eating well.  It's only the one fish. Any suggestions ?   The PH is between the 6.5 to 7.0 area, temp is kept as close to 81 degrees as possible. <PH sounds kind of low.  Have you tested for ammonia?  How big is your tank?  Those fish are high waste producers, creating a huge bioload.  I suggest 50% weekly water changes & serious filtration!  I actually do that on all my tanks.  Are you aware that Pacus supposedly can grow up to over 3 feet in length?  The fish is very round and thick. Wild specimens have been weighed in at around 70 lbs! A quarter sized baby will quickly grow to over 6 inches within a year. Because of the eventual size of this fish I recommend at least a 300 gallon for just one! Do not buy this fish if you don't plan on following through. They are a huge investment, but it's worth every penny.  Most of these poor fish is doomed to die at an early age or is cast aside and abandoned in a pet store.> Any help would be greatly appreciated. Thank you for your time sincerely Dave <Good luck with your giant fish.  ~PP>

Pacu teeth and food/wafer evaluation I just thought you guys would be interested in a little product assessment considering algae wafers and Pacus. My Pacu is nuts over Algae wafers, so I've been shopping around for the ones that would be best for him. The two I've been using are pretty much the same as far as ingredients go. These products are Top Fin and Hikari, I've found that Hikari are actually better in two ways: they are about a dollar cheaper and have a half an ounce more in weight, also the wafers are a lot tougher and Pacu likes them that way because they feel good on his teeth. He actually takes the time to chew them and you hear a crunch that you can hear from the opposite side of the room. So there ya go, they are better for Pacu owners. Since I started feeding this to Pacu his teeth have grown in more plentiful and there are any tell tale signs for sore teeth anymore. Of course he gets a very plentiful diet of what ever just happened to be in my salad that night too. (No dressing of course) He seems to like grapes a lot too. <Thank you for this input. Will post/share... you've made many Pacus happy with your testing, reporting. Bob Fenner>

Moving... a large, crowded Pacu 7/14/05 Hi, <Hello> We will be moving soon, and we are wondering how the heck we are going to do so. Since our Pacu is now about 2 feet long and 1 foot tall. He is currently in a 60 gallon tank which we upgraded for him 2 years ago. <... too small> He use to be in a vertical 45 gallon. Anyhow, the last time we moved, he suffered a fractured tail; he jumped out of the bag, landed his tail on the edge of the bucket, and flopped on the floor. It was a nightmare!! <Think about the fish> Since then he has grown a few inches, and we don't want the same thing to happen again, do you have any suggestions? <Yes... this fish is best removed from the tank with the use of large, thick plastic bags (pet fish or trash can variety), perhaps doubled, tripled for strength... slowly, deliberately scooping up enough water, the fish... and enough strong arms present to lift all out of the tank... then using oxygen gas to fill the bag/s, seal... and expediently move> Also, how to you travel 400 miles with a fish that big, without killing him? Shoselyn Novo <The oxygen will help... but perhaps it's best to leave the fish with someone, a shop that can/will ship it to you (air) after you're situated. I must state that this is not an adequate space for this animal, species... Unless you're able, willing to provide something of a few hundred gallons, I would find it another, better home. Bob Fenner>

Pump selection... misplaced priorities 7/12/05 Hello, I was shopping around for water pumps in mail order catalogs. I'm looking for something with raw, unrestrained power <Good terms> that can create a current big enough for my 20 inch Pacu to swim against in a 90 gallon tank, <... yikes, you need a much larger system for this fish... MUCH> but it needs to about my budget, oh say around $65. I did find a via aqua pump, fully submersible, 1,321 gallons per hour at $59.99 from Drs. Foster and Smith. Do you guys know of anything with more power for about the same price? Doesn't necessarily have to be fully submersible, and I'm not worried about sound or power usage, it wont be a 24 hour thing. Thanks a bunch! You guys are great! <... I would not be so concerned with the purchase price here as much as the operational cost... electrical consumption will be more than the pump cost within a year. Look to the Eheim line IMO... more to invest in up front, but quiet, long-lasting, energy conserving units. Bob Fenner>

Re: Colossoma, human nature 7/13/05 I think you'll find this story quite familiar as I've been getting advice from you guys for a while now, but the fish is in a much better condition than he was before. I originally bought him in  an 80 gallon with filtration adequate for maybe a 50, and he had 2 huge balsa, 4 full size silver dollars, a giant Pleco, a jack Dempsey, couple Corys, and a Gourami with him. now the 80s been fully upgraded and the Pacu has been moved to a much nicer 90 gallon all by himself. The 90 gallon has about 750 gph of filtration at this time. Keeps him sparkling clean with gravel washing once, sometimes twice a week when he decides to eat more. The previous owner actually had no idea of what to do with him, and his wife was tired of cleaning the tank DAILY! Can you believe that? Scrubbing an 80 gallon tank every day! <Too much life, too little space, filtration. RMF> But right now I'm out of a job and low on money. But my parents (I'm 17) plan on building a rather large green house in a couple years. Well, they decided to make it even larger to accommodate a 300 gallon heated pond design that I plan to custom build above ground for Pacu. He should be happy in that system to the end of his days I think with plenty of other small fish to swim with and lots of plants to eat. <If it lives in the meanwhile> Right now I can tell he'd like some moving water as some times he goes to one side of the tank, puts his nose against the glass and swims as fast as possible against it sending sand and his one plant everywhere. Good for keeping detritus out of the gravel, but when he's done the tank doesn't look so beautiful anymore. So I thought maybe a good strong current for part of the day might get him some exercise. What do you think? Open to any ideas. I will check out the Eheim pumps, that sounds good. Thanks again! Here's a link to a picture of Pacu's tank for you to see how clean and healthy he is! If only I could get a job doin this kinda thing! http://www.deviantart.com/view/17741252/ The Pacu and the Gourami you see here have since been removed to the 80 next to it, and the Jack, due to poor accommodations for an aggressive fish, was given away to an enthusiast with a 150 gallon tank. last I heard the jack hit a BIG growth spurt and is developing a small frontosa style lump on his head. Polara_Blues

Ongoing Pacu in a tiny tank, pump... 7/14/05 Thanks, I've been doing everything I can to keep him healthy, he is currently disease free as far as I can tell, and his tank is always clean enough that he almost never has to open his mouth to breath hard. I'd get a new tank for him in the mean time, but 150 gallon cube style tanks run up over $1,500 in my area, that's without a lid and filtration. Fat chance on finding a used one too. Even though Pacu is the most important thing here, I have to stop my self from taking out a loan. Polara_Blues <I would donate this animal to someone or an institution who can/will care for it. Bob Fenner> Re: Hmmmm...I might think about that. Polara_Blues <Ah, good. BobF>

Poor Pacu, Cramped Quarters - 08/23/2005 Hi.  I saw your website and thought I'd try this question.  I'm an intern at a Baltimore hospital which has a 28 inch Pacu in a small tank.   <Yeeee-IKES!> Apparently no one knew it would grow this large when it was purchased several years ago and the Baltimore Aquarium won't take it and they can't put it in the bay.   <Certainly not.> So no one knows what to do with it, and it's too big to even turn around in its tank.  Do you have any suggestions for situations like this?   <Well, this will most certainly be posted on our dailies....  If you like, you can offer contact information for us to post with it, in case a reader wishes to contact you to offer a new housing arrangement for the animal....  Otherwise, you might try offering it on Aquabid.com or Ebay.com, or check with the local aquarium clubs in your area to see if they have any members that would be interested.  As a last resort, you could check with local fish stores to see if any will take it.  I hope it goes without saying that, once this animal is in a new, more appropriate home, do NOT consider another Pacu for this tank!> Thanks, W. Gilmer, md <Wishing you and your resident Pacu well,  -Sabrina>

Healthy diet for a Pacu   1/4/06 Hello, my name is Brian and I have a Pacu that is growing ever so quickly. <Heee, well-kept ones do>   I need some help with a healthy diet for my Pacu.  Right now the Pacu shares a 38 gallon tank with a Pleco.  I feed the Pacu cichlid sticks and algae wafers. <Good choices> I would like to start feeding him more home-based foods such as spinach, carrots, and other veggies that you may recommend to supplement the cichlid sticks.  It seems that the Pacu is growing at an extremely fast rate.  Hopefully the change of diet might slow it down.  Any and all help is deeply appreciated.                                                                                             -Brian- <A routine of "blanching" such terrestrial-based greens... what you list and pretty much any others that are solid, by microwaving or boiling for a minute or two on the stove... and allowing to cool is about all that is required here. Do be aware that there is a "learning curve" here... for the Pacu to understand what is food, how to eat it. And that these foods call for more water changes, filter cleaning... Bob Fenner>

Tom... need titles to find/match prev. corr... 9/28/06 ? Pacus, Serrasalmine IDs... Tom, <<Hi, Lisa.>> Oh, I'm so confused! Well, my cousin said that I had a cichlid? I know for sure that I had at least one I know for sure is a silver dollar. . . ( I had two) But maybe it's a Pacu? <<Could be... These two, and Piranhas, are sometimes confused at the juvenile stage. As they mature, the differences become more obvious.>> Is there any kind of difference between a Pacu and a Silver Dollar? <<Oh, Lord, yes! Sorry about the emphasis but if you have a Pacu as opposed to a Silver Dollar, you'll need a 300-gallon aquarium to keep it. Not likely, I'm thinking. :) Now, a Piranha might have a distinct taste for your other fish.>> I know for a fact it was eating my fish because one day I saw parts of what was left of my fish chomping on it! I really did get the memo.. Just its wrong.. ( haha) Yes, its very 'nervous' I can't even turn on the light in the tank and it goes crazy. <<Again, this is common of Pacus, which is why they fall into the "tank buster" category. They can/will "frenzy" themselves into anything and everything in the tank. Not what you want in a fish that reaches 30+ inches in length and can weigh upwards of 55 lbs. or more.>> My fish is not typical in any way. Oh, I think this is kind of funny. When I was cleaning my tank I noticed my fake plant had gnawing marks all over them. I wonder who that was from'¦ <<Silver Dollars and Pacus, both, will eat aquarium plants of just about any variety. (There are some plants that folks have found that won't get devoured but most of those that you'll find readily at the fish store will be turned into "lunch" sooner or later.)>> Okay for the filters'¦ even if you have charcoal, they don't get the bad stuff out- thought it got the 'invisible solids' out? <<Activated carbon does a very nice job of "polishing" the water of hard-to-eliminate solids but does nothing for ammonia and nitrites.>> Um, I usually clean the filter when it gets kind of bad. Hard to get the stuff out, I change it. I'm such a bad fish keeper! Definitely getting an F'¦ (haha) I'm guessing you are an aquarist yourself? <<Yes, indeed.>> If so fresh or saltwater? <<Strictly freshwater at this point in time, Lisa.>> Yes, I do wish there was more time in the day. That would be nice'¦ Lately I been going to bed kind of early 9-10. I guess my body isn't in the swing of school yet. Should I tell the person about the worms? Or keep and eye out on the tank? ( I'm scared to tell him.) <<As I suggested, Lisa, the problem is with the tank, not the fish. If your friend's tank comes down with Planaria, it will be due to water conditions in his aquarium, not the fish you gave him. You're off the hook! :)>> I'm sorry I'm bombarding with a lot of questions. Thanks, Lisa <<Any time, Lisa. Tom>>

Pacu Diet   2/14/07 Hey there, <Hey back...> I have a couple questions. <Ok....> I have two red belly Pacu one doesn't eat  what mite be wrong with him. <A multitude of things could be wrong/not wrong with him, fish go through hunger strikes for various different reasons.> Another question is I feed my Pacu algae  wafers what are some other good foods for juvenile Pacu? <Well you are on the right track, although they look vaguely sinister like their cousins (you know the one), Pacu's teeth are built for the consumption of vegetable matter...and only every once and a awhile consume protein/animal matter, usually insect/bugs.  For smaller specimens algae, wafers, Nori and flake food consisting of Spirulina would be my choice.  Adults are a rare exception, usually when talking about aquarium animals I usually recommend staying away from terrestrial vegetable but n this case...it may be okay.  (In fact one of the neatest things I have ever seen is an adult PACU chowing down on a large cucumber)...as for the PACU itself I will spare you the lecture on it's adult size and make a leap of faith assuming you have researched it's adult size and needs.> Thank you for all  the help. <Of course, Adam J.>  

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: