Would be great if we knew what the dose should be! If you don't know for sure, I'm not gonna risk it! Not if I can get this stuff from the vet.
I am hoping she has heard of this metro whatsit as she is American. After googling, some people have been to their vets to ask and they dont know what they are on about, which is worrying!

Usual dose is 125mg per 10 us gal for the water soluable stuff, but you have to be more precise if its a powder going into food. So you have to work out the concentration and measure it out accordingly. Youd work it out by average fish weight.

A vet not knowing what metronidazole is? Thats just them being crap. Might get more luck with a reptile vet or someone who specialises in exotics.Even most good vets with birds should know what metronidazole is.

Right am going to do the sums.....
I dont have a clue how much she weighs, this could be stressful, I dont have to weigh her do i?

Tank is 25.33 UK gallons, how many US gallons is that?

Thats 30 US Gallons or 113 Liters

Is this a dumb-ass question, I've had metronidazole before, is it the same one? Would it be OK to use human metronidazole on fish or are there other additives in it?

Fishy! Have you used it for yourself or for your fish?

Yeah its the same stuff, most vets will just buy in flagyl s, and its all manufactured for human consumption anyway. Ive used it on discus (lets face it , if it wont kill a discus, what is it gonna kill? lol)and several other cichlid species before and they get better and do fine. Metro is known for having a pretty safe overdose limit. A lot of folks work it out so that overdose isnt more than 2x and thats considered close enough, then they just prep the powder in gelatin, mix it up with mashed shrimp or something tasty to disguise the flavour, and feed it to the fish.

I guess you could weight the fish by putting a jug with water in on some scales, hitting the tare button and then just drop her in for a few seconds,take the reading and then tip her back into the tank, failing that an educated guess would probably do.

dammit, I just very nearly calculated the weight based on the volume... then lost the post. Basically working on the fact that she is basically an oval you can work out the volume by averaging length and width and calculating as a sphere.

Obtain the radius of the sphere. It's the length from the center of the sphere to the side.
Cube the radius. So, if the radius is 2, cubing it would be 2 x 2 x 2, which is 8.
Now, multiply the result by Pi, which is approximately 3.14.
Multiply this by 4/3 for your final answer.

I estimated an average 12cm diameter which is 6cm radium.

This gave me 904.3 cubic cm


Now then 1 cubic centimeter of water weighs 1gram

so thats equal to 904grams... of course this is all theory - anyone like to confirm likelyhood of it being right?

But how does the density of a fish compare to the density of water?!
I'd catch her in tupperware box full of water and weigh that, then release her by lifting her out by hand and weigh it again myself

edit: I think Mr C had flagyl from dentist for abcess - got any dentist friends?