Dead Betta... why?

[bigredspecial]

I just discovered my Girlfriend's male betta, Luck, had died. Now the investigation begins... I can't, for the life of me, figure out why. there was no visible signs of any illness; no lesions, abnormal swimming, anything. Before he died, he was in the corner of the tank, sitting on the gravel, breathing heavily. His gills looked a little brown, so i suspected Nitrite poisoning, so I whipped out the test kits:

pH: 7.2, stable
NH4 - 0
Nitrite - 0
Nitrate - <10ppm
Temp is stable at 25 degrees C

Keep in mind, this is a 2.5 hex; all that is in there is/was Lucky, two guppy fry, a air driven sponge filter, and a few plants. He was eating normally up untill last night.

Any ideas what the problem could be? The guppy fry are fine.

 

[Fuzz16]

old age possibly?

 

[MissFishy]

The nitrates were above 10? If they were above 10 for a long period, that could have taken its toll on him, but like you said, the guppy fry were fine. Could anything have contaminated his food or the water? What was the temperature?

 

[CAPSLOCK]

Nitrates above 10 isn't going to harm a betta. Not sure what it could have been though... contamination would have likely killed the fry too, and when they get old they tend to get lethargic for a period of time.

 

[IDunnoWhy]

Well my first guess would have been old age, My old male did something similar, howver your saying the gills had a brown color to them..This may imply some sort of infection, however the other fish would be showing similar signs I would think.

Keep an eye on the remaining fish, and I would certaining do a partial WC and see what happens.

 

[bigredspecial]

I have been keeping a eye on the others; so far they're fine. It definately isn't nitrAtes, 10ppm is nothing for a freshwater tank, and many people actually reccommend ~10 for planted tanks; mine were actually below 10.

I considered old age, but I don't think that's it; this all happened way too fast. He went from healthy and active to dead in the space of 1.5 days.

Right now my only guess is some sort of gill disease or parasites.

 

[MissFishy]

pH: 7.2, stable
NH4 - 0
Nitrite - 0
Nitrate - >10ppm
Temp is stable at 25 degrees C

I said the nitrates could have been a cause because you say ">10" meaning the nitrates were over 10, but give no figure. If the nitrates were too high, it could certainly be the nitrates. However, you say it was exactly 10 now. So that wouldn't have been it.

If it is some sort of disease, keep a close eye on the rest of the fish and do a water change. Some melafix wouldn't hurt either.

 

[bigredspecial]

yeah iI meant to type <10, Oops! I've edited my original post.

Besides, guppy fry would get hit long before a betta would if it was a water quality issue. The fry is fine, and a water change won't do much, considering the tank gets them twice a week anyway.