Aging Gourami

[whfffft]

I have a well-established, apparently healthy 10-year old, 10-gallon tank.  It's  well-planted and I change out a gallon every two weeks.  Current population is 2 4-year old black skirt tetras,  a corydora, a small plecostomus and an eight-year old blue gourami.  Until yesterday, the gourami looked healthy - active, good appetite, no fin or scale problems, no bloating or shrinking.  Last night, without warning (no bells or whistles!) it developed a marked lateral spinal curvature, to the point that it's now nearly s-shaped.  No loss of activity, no loss of appetite.  Is this possibly just an effect of its advanced age?  My daughter's had this fish since she was in kindergarten (she's named it Facebook), but she wants me to put it down if it's "suffering".  Since it appears otherwise healthy, I'm reluctant to do so.  I think it may be going for a size (6 inches) and age record!!  Opinions?

 

[fluttermoth]

Hi there, welcome to the forum

It could well be old age, as bent spines are common in old fish.

However, it could also be the effect of long term exposure to nitrates. I'm sorry to say that your little tank is pretty badly, and very heavily overstocked, and your water changes are nowhere near large enough, or frequent enough, to be keeping nitrate at an acceptable level.

If you don't have test kits of your own, you should be able to get your local fish shop (LFS) to test it for you but you must make sure they give you the actual numbers, not just say, "fine" or " a bit high".

You will need to up your water changes, but you must do this slowly, as the fish will be used to the water they're in now, and you could shock them, if you change too much at once. Your tank is almost certainly suffering from what we call 'old tank syndrome', where the water has gradually got softer, more acidic and has very high nitrate levels.

The other possibilities would be bacterial infections (but the fish would be showing some other symptoms, if that were the case; lethargy, loss of appetite, white stringy poo) or 'fish TB' (but that's very, very rare; in 30 years of fishkeeping, I have never seen it, and it would have to have been introduced by another fish; it can't spontaneously appear from nowhere).

It is very difficult to tell if a fish is 'suffering', although they certainly do feel pain. If you feel you do need to euthanise, you can use either clove oil (we can give you guidance on using that, if you need it) or a hard blow to the head (if you're a tougher person than I am!).

I'm sorry your fish is in a bad way, and that I can't give you a cure

It's awful to lose a fish you've had for a long time.

 

[whfffft]

Sorry.
That's a 10-year old, TWENTY-gallon tank