Hi- being new to fishkeeping myself, I understand how upsetting it is when there's something wrong with the tank and you just can't figure it out, or know what to do to stop it. I had a German Blue Ram who I just loved get sick and die a few weeks ago, seemingly out of nowhere. All my water conditions were perfect, I still don't know what happened. Anyway....back to your problem.....
Without diagnosing the disease/parasite/fungus, I don't know if there's anything you CAN do aside from keep your fingers crossed...
Do you have a local fish store? If you have a dead fish that you haven't thrown away or flushed, I'd bring it in to the aquarium store along with a water sample and ask them what it is. They'll tell you how to medicate......
How long are you going to London for? It's very nice of your friend to take care of your fish, but you should make sure that she has as much information on exactly what to do as possible. Also, it's very easy for fish to get overfed by well-intentioned, over-anxious sitters. Whenever I go away, I pre-measure daily rations for my fish and put them in pill-boxes (the kind that has each day of the week separated into its own compartment- I got them at CVS). That way, all the sitter has to do is pop the box and dump it in.
You may have already done this, but I think you should leave her with a full list of what fish you have and ask her to count them every day (this is particularly important since you've been losing fish). It's very bad for the the other fish to have dead fish rotting in the tank......she needs to know to look for them if they're not swimming around and to fish them out if she finds them.
One last thing.....Depending on how long you're going away for and how invested you want to be in this problem....perhaps tomorrow morning you might want to pick up an inexpensive 10 gallon tank and filter to create a hospital tank......you can put the fish you currently have in the vase in there and if another fish looks suspicious while you're away, your friend will be able to separate him from the rest.
Good Luck! Let us know what happens.
Without diagnosing the disease/parasite/fungus, I don't know if there's anything you CAN do aside from keep your fingers crossed...
Do you have a local fish store? If you have a dead fish that you haven't thrown away or flushed, I'd bring it in to the aquarium store along with a water sample and ask them what it is. They'll tell you how to medicate......
How long are you going to London for? It's very nice of your friend to take care of your fish, but you should make sure that she has as much information on exactly what to do as possible. Also, it's very easy for fish to get overfed by well-intentioned, over-anxious sitters. Whenever I go away, I pre-measure daily rations for my fish and put them in pill-boxes (the kind that has each day of the week separated into its own compartment- I got them at CVS). That way, all the sitter has to do is pop the box and dump it in.
You may have already done this, but I think you should leave her with a full list of what fish you have and ask her to count them every day (this is particularly important since you've been losing fish). It's very bad for the the other fish to have dead fish rotting in the tank......she needs to know to look for them if they're not swimming around and to fish them out if she finds them.
One last thing.....Depending on how long you're going away for and how invested you want to be in this problem....perhaps tomorrow morning you might want to pick up an inexpensive 10 gallon tank and filter to create a hospital tank......you can put the fish you currently have in the vase in there and if another fish looks suspicious while you're away, your friend will be able to separate him from the rest.
Good Luck! Let us know what happens.