I've been reading a lot on the infamous rtc lately, I've owned a few wich I've moved on before they got too big but there's a lot of people here who've done the same right? My local fish store had one when I was 18 in an 8x2x2 at about 18inch so I'm guessing about a year old, before it could touch both sides front to back it was upgraded along with its tankmate a large black pacu to a 1500 gallon tank. I'm now 30 and both fish are still in the tank, rtc is 27inch and the pacu is about 22inch. I'll get a pic next time I'm there, water has always been clean and the fish very active! Has anyone seen this before? Most rtc I've seen stay considerably smaller in captivity than the amazon! We know ir sharks stop growing around 2ft in the aquarium, what's the average size of a captive rtc, not including public aquariums?
rtc 27 inch long 13 years old?!
- Thread starter justarn
- Start date
iridescent sharks don't stop growing at 2 ft in captivity, their growth slows down. RTC when properly cared for and well fed long term will approach 4 ft.
the fact that both of those fish are undersized means they are probably either stunted or long term underfed
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the fact that both of those fish are undersized means they are probably either stunted or long term underfed
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IMO the LFS's RTC was probably stunted. I don't know the average captivity size as some of the ppl on here have much larger ones in their ponds or in their monster tank setups. Though in my own experience with them I've raised 4 RTC's before and largest I grew one too would be from 3"-22" in about 1.5 years in a 250 gallon tank. My last RTC I raised grew from 7"-20" in 6 months in a 450 gallon tank. If i kept them longer they'd probably would've grown much larger. Given proper housing and care for them I'm sure they could reach 3+ ft in the home aquaria.
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Yeah I guess, looks plump tho! Both were rescues, the pacu was a pet when the gf of the owner tipped detergent in his tank during a row, the red tail was dumped outside his shop... So stunting is likely. I've been thinking my next setup will be a pond, just finished my 300g for my lounge. On ebay here in the uk they do flat pack ponds 10lx6wx4d cheaper than my tank cost me!-) missus would go mad haha!
Stunting at an early age can and will affect the growth of the catfish. Most people I believe don't feed large catfish for growth. Once they are over 2' most people feed them what I would call a maintenance diet. They get just enough food to maintain their growth and maybe add a few ounces per year. At that rate it would take a very long time to get them over 3'. Personally I like to see my fish thrive and reach their full genetic potential. It's hard to say anything about a lfs water quality or feeding regimen. I know of a fish store in my home town that has had a rtc in the same 300 gal tank for nearly 30 years now. It is about the same size as the one you mention. After many talks with the owner he only feeds it about once every two weeks. Large catfish can maintain healthy bodyweight for long periods of fasting. I've had catfish go for 6 month hunger strikes and barely lose enough weight to be considered unhealthy. They still had backs full of muscle ect. Catfish are perfectly evolved for survival in tough conditions. Monster fish keepers should not settle for their fish surviving, we should ensure our fish thrive! 
JMO. I know from raising several rtc that with proper diet, frequent water changes, heavy duty filtration, and plenty of space to grow that they can reach 3' in two to three years. I've had one hit nearly 2' in less than a year from 1.5". I do tend to feed rtc more often than most. I go based on their belly. When their belly is flat I feed, when it is plump I don't. I also feed them things that are easy to digest quickly. Shrimp, fillets, ect. i would like to see someone on here raise a rtc in a large tank that could support a 3' fish. Start with a very small rtc and feed it aggressively as well as doing aggressive water changes. Keep conditions near perfect and see how long it takes to get to 3'. Measure it in tank monthly, do not move or remove the fish from it's enclosure until after it hits the 3' mark. Stress can cause hunger strikes. You will want to avoid that.
JMO. I know from raising several rtc that with proper diet, frequent water changes, heavy duty filtration, and plenty of space to grow that they can reach 3' in two to three years. I've had one hit nearly 2' in less than a year from 1.5". I do tend to feed rtc more often than most. I go based on their belly. When their belly is flat I feed, when it is plump I don't. I also feed them things that are easy to digest quickly. Shrimp, fillets, ect. i would like to see someone on here raise a rtc in a large tank that could support a 3' fish. Start with a very small rtc and feed it aggressively as well as doing aggressive water changes. Keep conditions near perfect and see how long it takes to get to 3'. Measure it in tank monthly, do not move or remove the fish from it's enclosure until after it hits the 3' mark. Stress can cause hunger strikes. You will want to avoid that.I haven't raised mine up from babies but I got them at 28 and 30 inches about 6 months ago and even with pretty heavy feeding every 5-7 days(I like to feed my fish), they've only grown about an inch. I feel like they slow down considerably when they hit 27,28 30 inches but i have no doubt that my fish are still growing and will break 3 ft in a few years.
I will also say that I've never seen a rtc over 40 inches in a private aquarium. Not saying it doesn't happen but I've never witnessed it. I don't believe they will hit 4 ft with any regularity in anything less than arapaimags 50,000 gallon personal ocean.
It sounds like stunting is a likely cause, but it should also be noted that like all other organisms, not all RTCs will reach the same size. Right now I'm at a fish farm with 50,000 sturgeon and I can tell you that there are some large differences in size between fish that were hatched at the same time. Maybe this RTC is also a runt?
Stunting at an early age can and will affect the growth of the catfish. Most people I believe don't feed large catfish for growth. Once they are over 2' most people feed them what I would call a maintenance diet. They get just enough food to maintain their growth and maybe add a few ounces per year. At that rate it would take a very long time to get them over 3'. Personally I like to see my fish thrive and reach their full genetic potential. It's hard to say anything about a lfs water quality or feeding regimen. I know of a fish store in my home town that has had a rtc in the same 300 gal tank for nearly 30 years now. It is about the same size as the one you mention. After many talks with the owner he only feeds it about once every two weeks. Large catfish can maintain healthy bodyweight for long periods of fasting. I've had catfish go for 6 month hunger strikes and barely lose enough weight to be considered unhealthy. They still had backs full of muscle ect. Catfish are perfectly evolved for survival in tough conditions. Monster fish keepers should not settle for their fish surviving, we should ensure our fish thrive!
Well put necrocanis. I thought about getting a regular RTC for my 600g 8 x 4 footprint but I worry it'll eat my other prized stock I want to get. I am looking for a Short body RTC instead and would like to see how big it'll grow to. I myself also like to feed my fish well and see them thrive.
I know it wasn't directed towards me but keep in mind that the short body rtcs have pretty much the same sized mouth as a regular rtc and isn't the best choice if you're hoping that they won't eat your other stock...also, I think they look like giant sperm lol.