My oldest guppy (I've only had it a few months, but I assume it's old- she's about 2 1/2 inches) has been becoming increasingly shy among the younger fish (almost all of which were her own fry) and hides in the giant patch of java moss with her grandchildren. I only see her eat about every other day, and she is slowly going from a grayish gold to a dark brown through most of her body. Should I be worried about this or is it simply old age? Do you think she'd be happier if I bought her her own small tank?

Could be old age. Water chemistry okay?

I have a Marigold Platy that I got from the fish store that looked okay when I got her. She gave birth a couple of times and now doesn't produce anymore young and just sort of hangs out in the tank. She eats fine and everything else. I've had her for about 4 months. I think this fish is close to a year old, if I had to guess.

From what I understand, it's an old breeder trick to give up their older breeding fish and they sell them to the fish store or you. They all look the same, so you never know. Not to say all breeders do this.

She could be stressed with the increased population in your tank.

I know she's probably pretty old. All my other guppies are maybe three months and only an inch long other than the week old fry she is currently hanging out with. She has only had two batches of fry, none since, I figured since she's in a tank of her own babies.

I don't think it's a water problem- the rest are all just fine. She seems to be the only one acting out of the ordinary, and it's been slowly growing more noticeable. I think of her as the cranky old lady who just wants to be left alone, but I realized I should probably ask here just to be certain. She's the only one left of my original three- one developed bloat and the other developed ick like symptoms and passed on, but I never quite figured out what it really was.

If the population is an issue I'll just buy her her own five gallon and keep it next to my big tank no problem. I love her, she has a pretty yellow and black speckled fin.

Update. Came home from work and have more odd behavior to add. She's swimming around like she is drunk, and if she drifts into the stream of water from my filter she can't resist the movement of the water and just kind of drifts with it.

I have some females that look like that. Unfortunately, it sounds like she could end up dying. I have one though that has been that way for over a month. I keep hoping she'll get better and she is in a 20g by herself, but I think she'll son pass.

I kind of think that might be the case. From what I've seen she's a full grown guppy. She hasn't really gotten any bigger since I got her (I think) but if there is anything I can do for her I want to. =[

Update. Got her her own tank. She won't eat, and her tail is crooked. I've been putting some spirulina powder in there a few times a day as it is the only thing she will touch, but she's lost a lot of weight and I haven't seen her eat it- the only reason I know she is is that I find small bits of feces every once in a while in the tank.

I bought some parasite guard from petsmart made by tetra and put it in my tank and it helped a number of my fish. If she has no outward sign of problems then she may have internal parasites. Maybe you could try that?

I ordered the "better" stuff by jungle labs called parasite clear.