Platy Vanished From Tank

[denismen]

.
I have 3 platy...2 female and 1 male and have been treating them for Velvet disease.
One Platy was gasping at the bottom of the tank last night a few hours after I added medication and increased temperature to 82 degrees so I increased the oxygen by adding an extra strong filter.
This morning the platy had vanished from the tank and I think he was eaten.
I also have a Plec and Blackmoor goldfish that are 5 times the size of the Platy.
The male platy has been bullying the missing fish for a few weeks now and she had just had some fry a few days ago when her conditiuon deteriorated.
I assume something ate the platy overnight after she died or showed signs of illness and wondered if anyone can throw some light on this.
Also can anyone tell me how much water my tank holds..it measures 31.5 x 13.5 x 16 inches...a Fluval tank.
I just bought it last week secondhand and was told it was a 125 litre tank but I think it may be smaller.
I was looking forward to my fish getting better and moving them to their new tank next week after the water sorts itself out.

 

[HAMBONE]

if my math is correct, you has a 46 gallon tank

 

[denismen]

Tnx for your reply.
I think u may be wrong though cos thats about 210 litres.
I checked yesterday at this forum converter and it said it was half what you say

 

[phantomlink]

That tank size is 29 US gallons ( 111 liters ) it sounds like its one of those general walmart style 29 gallon startup kit tanks. Did you check around your tank? I know when I setup my 125 about two weeks later or so, I found a platy behind the tank dried up, he jumped out of the tank through the small 1 inch slit in the back thats not covered

 

[denismen]

Tnx for the advice.
I saw the same tank in Pats at Home store 2 days ago and it says it is a 125 litre but I suspect you would need to fill it right to the top nearly to get that much and your 111 liters is closer to the mark.
No Platy has jumped from the tank but I did notice she was not well the previous evening so I suspect she died and was eaten by the other fish, which I have been told is normal behavour.