The case of the missing cardinals.

[Wulfy]

I have a small group of Cardinals in my tank (11).
The only other inhabitant is one Bristlenosed pleco (the size of Cardinals).

Over the last week I have lost 3 cardinals.
There are no bodies.
It happens at night.

One thing I did observe that the cardies are not as
ravenous when I feed them, especially in the morning.


My theories are;
1. Desease (no outward signs tho).
2. Pleco eats them when they are asleep.
3. A mouse/rat dives in the tank (!)?
4. A geco lizard dives in the tank (!)?

Can anyone offer suggestions why theyre going?
My most up to date water stats.
Temp:86F
Ph: 6.3-6.4
Nitrate: 5mg/L
KH: <1 Khd (I know its low, but I cant bump it up without raising Ph).
Gh: 2 Ghd

I have CO2 and the plants look nice (all but the grasses).

[NJ Devils Fan]

I strongly doubt that the pleco would eat any fish. It could be that they are dying and all the other cardinals are eating them. I think though that your water is a bit warm for the fish. You should lower it a few degrees to about 78-79 ish. They might be sluggish to go for the food because it is so warm, then, the others might be eating the weak ones instead of the food. I have absolutely no clue if this is right, but it's just a suggestion.

[thom336]

I would definately bring down that temperature....
but i dont think that is what is killing your fish. It is most probably a disease of some kind - and once they die the pleco is most likely clearing up the corpses for you, with the help of the other cardinals. It could just be coincidence that the three cardinals died around the same time...
Try varying your fishes diet, as this should make them more ravenous, and skip a feed every couple of weeks or so, this should help those appetites. Hope this helps.

[Tempest]

You probably had ought to raise the Kh to 3 or 4 with some baking soda then use the CO2 to control the ph. I don't think your pH will be stable with such a low kH. Your pH level then would be more like 6.7 I think..

Here is a link to a good reference table for it.
http://www.sfbaaps.com/reference/table_01.shtml

[Tempest]

Ooopsies... You have a real low gH too so you might want to raise both of them for the plants /and/ the fishies sake. I"ve never had that problem with our hard water but some here use minerals to do this..