fish size in captivity

Oh man lose the channel cats. I had one go from 4" To over 15" in less than 1 year.

He said 4g per inch, not 4g per fish. And keeping them in a small tank won't stunt them, fish will continue to grow regardless of tank size. Its the poor water quality brought on by inadequate housing that stunts fish.

Eh, I tend to disagree. While you're right that the two species don't normally make good tank mates goldfish are tolerant of a wide range of water types, I wouldn't consider them coldwater. More like sub-tropical, they do fine at temperatures that work well for most tropicals.

It isn't just water temp that makes them incompatible--sooner or later, those goldies are going to start nipping at the betta. I've got 6 bettas right now, and I've had as many as 14 in the past, and I'd never keep them with goldfish.

And whoops, I read it as 4 gallons per goldfish. 4 gallons per inch of goldfish sounds much better. And yeah, it's the water quality in the small tank that would keep them from growing, because it'd be almost impossible to keep it decent with big goldies in a small tank.

It isn't just water temp that makes them incompatible--sooner or later, those goldies are going to start nipping at the betta. I've got 6 bettas right now, and I've had as many as 14 in the past, and I'd never keep them with goldfish.

I realize temperature is not the only limiting factor. In my initial statement I said "While you're right that the two species don't normally make good tank mates goldfish are tolerant of a wide range of water types"

Edited by sandtiger, 08 November 2008 - 05:25 PM.

I realize temperature is not the only limiting factor. In my initial statement I said "While you're right that the two species don't normally make good tank mates goldfish are tolerant of a wide range of water types"

I saw the "I tend to disagree" part and assumed you were saying bettas and goldfish could live together, sorry. I've been dealing with the idiots on Yahoo! Answers for too long. It fries the brain.

And do you ever test for nitrates? I lost half a tank to a nitrate spike before I realized what was happening.

I test all parameters (except ph) no less than once a week. I also do a minimum of 25% water changes every week, sometimes more on the two smaller tanks because more water leaves when I vacuum them. I have 10 ppm Nitrates coming out of the tap, tanks usually run about 20 ppm.

Also, bettas + goldfish = HUGE no-no. Goldfish are coldwater, bettas are tropical, so one of them will be suffering if they're both in the same tank. And the goldfish will eventually start picking on the poor betta.

I did a little research and I understand that Bettas do best in 78-82 degree water. So far the water has never dipped below 75. FWIW, the Betta was nipping the fins of one Goldfish quite a bit but that has since stopped. The Betta seems to be the dominant one in the tank. Also, I understand that Golds are cold water fish, but last Summer the temp in all of my tanks rose above 80 degrees. I noticed no change in the Bluegill's behavior compared to lower temps, and I doubt I'll buy a chiller for the Goldfish.

The tank is in a spot where we can stare at it any and all of the time. Lots of fake plants to hide out in and explore. All four of them are always on the go. Again, the water is always excellent. If the temp drops much below 75 degrees I'll add a heater to keep it above that and if things start to look crowded I'll do something but right now they look to me like they have room to stretch out. Tank is 18" long, 11" wide, 12" tall with about 1.5" of substrate on the bottom.

Edited by Sombunya, 09 November 2008 - 01:28 PM.

*shrug* I wish I could change your mind. Bettas can make excellent community tank inhabitants if you know which fish to put them with, and they do best with a constant temp of about 80 and little to no current. Goldfish certainly don't need chillers unless the water temp is constantly in the high 70's/80's, but they do like cooler water. Here's a quote from a very reputable betta forum I frequent:

"Improper housing aside, the two species are incompatible. Bettas are small, solitary, aggressive tropical fish which require soft, acidic, still water and pristine conditions. Goldfish are large, social, fin-nipping coldwater fish which demand harder, slightly base, well-oxygenated and filtered water. They are also massive waste producers and hosts to many parasites. In short, the two species are utterly incompatible, and should not be housed together under any circumstances"

I don't want to sound like I'm nagging, I'm just concerned.

Edited by Runan, 09 November 2008 - 03:15 PM.

I like to think that I take pretty good care of my fish. Right now the water is about 74 degrees. In the summer it was as high as 87 degrees. I will be looking into a small heater as winter is coming and my house will cool down a bit. If there was any less water movement it would be pretty much still because the filter is not what you'd call over-sized for the tank. There is no cover on this tank. I understand that Goldfish are considered large waste producers. That's why we check that tank three times a week as opposed to once a week for the others.

My water service here is from a ground source. Ph runs in the mid to high 7 range. I do not adjust the ph on any of my tanks, and I don't plan on buying a R.O. unit.

The "poor" Betta was nipping the fins of one of the Golds. It has apparently stopped doing it because the Gold's fins are growing back. The Betta's fins are long and flowing. No damage there.

As I am writing this the wife just fed them a little bit. I watched the Betta eat a large, sinking flake.

A while back I introduced a rather small Bluegill to one of my tanks and then had to move it, at my wife's urging, because it was being chased mercilessly. I kept it in the 20 until it grew another inch longer. I watch all of my fish.

I'm no expert, obviously, but if the Betta acts so much like the others you'd think they were all the same breed. All four of them are poking around in the heavily (fake) planted tank. Again, water quality is always near perfect (0 Nitrites, 0 NH3, 20 ppm Nitrates). Is this a perfect Betta habitat? Probably not. I'm not sure what a stressed out fish looks like but I don't think these are at all.

This thread has drifted a bit from the original questions.

The single most important limiting factor to growth of fish is water quality, with temperature and diet coming into play.

If a fish doesnt get a proper diet, with enough protein it cant grow. Then, if its environment doesnt dispose of wastes it will be stunted through increasing nitrogenous buildup, hormones/pheromones, and ultimately poisoning. Frequent water changes is a major need. The oft quoted '10% per week' is a bare minimum. 40-50% water changes are far better.

in the winter fish growth slows down, depending on the temperature. The colder the water the slower the metabolism and feeding rate.

Add in tank mates that are tolerant or causing stress and you have complicated the situation more. Stress reduces feeding activity, and threatens overal health.

Putting predatory fish like Catfish and Bass in with smaller fish is simply setting up trouble eventually. Extremely fast growing fish like Catfish add wastes to the water in a geometric progression compared to slower growing fish maturing at smaller sizes.

Some species which come from quickly changing water habitat have much lower tolerances for nitrogenous waste products. A classic example is the Discus of South America, their water while acidic has minimal wastes buildup and changes continuously so they have low tolerance for water with wastes. Trout and other Salmonids are similar but from colder water. Bullheads have a very high tolerance for poor water conditions with reduced oxygen quantity.

Combining species does require knowing the habitat that the fish come from and meeting their needs, if you cant then you should choose different fish to put together. Myself I prefer single species tanks. You can make a community tank with tropicals easier then with natives. But its doable with natives.

"Improper housing aside, the two species are incompatible. Bettas are small, solitary, aggressive tropical fish which require soft, acidic, still water and pristine conditions. Goldfish are large, social, fin-nipping coldwater fish which demand harder, slightly base, well-oxygenated and filtered water. They are also massive waste producers and hosts to many parasites. In short, the two species are utterly incompatible, and should not be housed together under any circumstances"

Update here on the Betta; I've been noticing it has been a bit listless here lately so I went to my LFS and the very knowledgeable owner pretty much echoed what you said so I moved it to a small tank with a heater, set to 78 degrees. I did this partly because she has Bettas in her store in small, filtered tanks with certain other types of small fish. But I will say I have been thinking about what you said.

Although these Goldfish are fancies I've noticed that when the water temp went down to 70 degrees they become more active. The Betta wasn't getting nipped but it was slowing down so I decided it's time to take some others advice. My LFS has a tank made just for Bettas so that's where I'm going at the moment.

Thanks for your input. I'll keep you posted.