Sickly red-eyed tetra

Julie's Julies

No, his spine is beautifully straight, and he does not have much trouble with buoyancy except for the slight list.

In all honesty, I think he was just severely under weight and when I transfered him to my tank, he succumbed to the stress because he was not healthy. I have tried playing "doctor" to my other fish, and I have found that leaving them alone seems to be the best thing. Transferring to the hospital tank stresses them out even further.

I really doubt he's going to pull through, but we'll see. Is there any way to force feed a fish?

mHeinitz57

not really but raising temperature will speed up the fishes metabolism and sometimes stimulate appetite. What is your temp at now?

Julie's Julies

78 degrees. Will raising the temperature negatively affect the rest of my fish?

bettababy

Everything you listed for fish would be fine if you raised the temp up as high as about 82 - 84 degrees, but watch the fish when you do this. Warmer water has less oxygen. If you see any of your fish gasping (rapid gill movement and/or mouth opening and closing rapidly, and gulping air from the surface) I would suggest adding an air stone until the temp is lowered again.

Julie's Julies

I actually already have an airstone in there in addition to my double bio-wheel filter. Both of these churn up the water pretty well. I was actually under the impression that cold water has a lower oxygen level - goldfish need extra aeration due to size and cold water - but does the oxygen level decrease again once the temperature reaches a certain level?

mHeinitz57

put simply, warmer water has faster moving molecules and therefore a faster release of oxygen. Plus, higher temps will raise metapolic rates and fih consume more oxygen as well. I've never heard of very low temps having a low oxygen content, not sure why it would.

bettababy

Goldfish need extra oxygen because they consume more oxygen than the average fish. Size and cold water are not the reason. There are many fish that grow larger than goldfish, yet don't have the oxygen consumption that goldfish do. It is a matter of physiology, and I'd have to do some research to find the exact reasons for you, as I don't remember what it is off the top of my head... but whatever the reason you were under the impression that colder water had lower oxygen content, that is not the case. The warmer the water temp, the lower the oxygen level. That doesn't work both directions with a cut off in the middle somewhere... as was already explained, it's a matter of molecules and can be explained with a chemistry lesson that I don't have the time to give right now. Maybe someone else here knows the details enough to take the time to explain that one for you.

With your current situation, if you raise the temp, you may find that additional aeration may be needed until the temp is lowered once again.
Good Luck!

mHeinitz57

Actually size and body temperature do play a large part in metabolic rate for any animal species. A higher metabolic rate will equal higher oxygen consumption. While goldfish do consume more oxygen than most fish (has to do with genetics and hormones) size and temp will cause changes in that oxygen consumption. Muscle mass and general surface area internally and externally play a very large role in resting metabolic rate. This is also part of the reason why goldfish require more oxygen...larger volume and less body fat. Body temperature does as well and since fish are cold blooded, that means their water temp affects metabolism. This is why koi can eat less (even nothing) in the winter time and then get very hungry in the summer...their metabolic rates change and that will directly affect their oxygen consumption. While there will be less disolved oxygen in warmer water, the summer time also means plant growth and more oxygen supply. When a large pond is frozen over, there won't be much oxygen available so its a good thing their metabolism slows down with temp.

The chemistry is actually very simple, when oxygen is "dissolved" in water it is basically just stuck within the bonds of water molecules. Higher water temperature will cause increased molecular activity and faster release of those trapped oxygen molecules.

It's important to see that as temp increases, the fishes need for oxygen goes up but the dissolved oxygen levels go down. Nature has a way of dealing with this as I mentioned before, greater plant growth. As fishkeepers, we have to make sure we compensate as well in our own tanks.

Julie's Julies

Wow, thanks for all the explanations! I actually have not raised the tank temp yet since it is supposed to be really hot this week and we don't have any way of cooling off our tanks.

He is taking bites at food now but he spits it all back out. I am feeding him the same brand and type of food as his former owner did, so I doubt it is that he dislikes it, but I am encouraged by this small attempt. His energy level is up just a little, too, so I will just have to wait and see.