Skitzoid Female Platy

[graceofbass]

I have a female platy that I originally thought had swim bladder problems, but now I think something is seriously wrong with her. She swims normally most of the time, eats, and seems fine, but then she will start somersaulting over her head in circles until she runs into something, like a plant or the gravel, and then she figures out how to swim upright again. It's almost like a seizure. None of the other fish are affected, the water is fine, and she is pregnant. I haven't introduced any new fish in months. I did increase the temperature of the water from 72F to 78F 2-3 weeks ago.

I don't have a full water testing kit, but there is little to no ammonia.
The tank has been set up for 9 months and the water is a little hard, but all the fish are used to it.
I have a Fluval 304 filter, bubbles to help keep the surface of the water moving, natural gravel and no live plants.

Any thoughts or ideas would be greatly appreciated.

 

[Gilli]

How big is the tank and what other fish do you have? Without a full water test kit you are not going to know your water quality. Even if there are traces of ammonia this will affect the fish - also what are your nitrite readings? - both these should be 0. What are your nitrate readings?

How often do you do a water change?

 

[graceofbass]

The tank size and all the other fish are in my sig. The ammonia is at .15, which while not zero I don't believe that would cause enough stress to make all my fish sick, which it hasn't. Also, I'm pregnant and can't lift the 5-gallon buckets I have to replace the water I take out, so water changes can only happen when I have help (which will hopefully be very soon). It's not a great situation, I know, but that's life.

 

[LauraFrog]

What are you using to test for ammonia? The most sensitive test kit I know of goes up in increments of 0.25ppm so what I'm saying is that yours probably isn't an accurate reading, and could be anywhere between zero and 0.75 really. Any trace of ammonia should not be showing in a tank that's nine months old. I suspect it's because the tank is overstocked. Do you know what sort of filtration it's running?

 

[graceofbass]

The test kit I have shows colors registering the different ammonia levels. The first color after safe is .25, but the test was not as dark, so I determined it was somewhere in the middle, between .1 and .15.

In my first post I said that I had a Fluval Model 304 filter. I keep it at half pressure so it won't suck any fish against the filter (which has happened before).

Overstocking could be an issue because of the number of babies I have, although they are all under 1/2 inch long.

Here's the current stocking and length:
3 adult marigold platies, all between 1 and 1 1/2 inches long.
3 juvenile & 7 baby marigold platies, juveniles between 1/2 and 3/4 inches long, and the babies are all under 1/2 inch.
5 neon tetras, all around an inch long.
3 zebra danios, between 1 1/2 and 2 inches long.
2 rasboras, about 2 inches long
1 male guppy, 1 1/2 inches long
1 male betta, 2 1/2 inches long
1 chinese algae eater, 3 inches long

I would appreciate more talk about possible problems with the fish, and less talk about chemicals. I understand chemical imbalance causes stress and illness in fish, but the rest of my fish are exhibiting healthy behavior, and this female's odd behavior seems neurologically-based to me.