Does it make any difference to have both an under gravel filter and a power filter in a 30 gal tank set up for fantail goldfish? Is it advisable to have one or both are fine. Please I need the input.

Avoid undergravels. They are a big risk when it comes to goldfish. Somepeople do use them but I have seen too many posts here about their being a breeding ground for toxic gunk. It's fine for a while and then eventually the crud at the bottom becomes full of harmful bacteria. I would use anything but that.
Jees Fish! Is that the filter you've had up until now for Comet? If so it could be very significant.

I'm sorry to say that when I started this hobby the people at the pet store told me that that would be the best setup for goldfish with both the undergravel and the power filter as it provides two modes of filteration instead of one. The tank has been doing fine so far with all the upkeep I do. Nipper is doing fine too and we got Comet and Nipper together. Comet had stability issues from the time she was very little.
OMG I feel sooooooooooooo bad but till now I never had any problems. Should I remove the undergravel from the big tank. I have never had such good advisors like you all at this site and this is my first time with goldfish. I truly am sorry if I did the wrong thing . Please advise what to do with the big tank so Nipper can stay healthy and live long. I truely have given the fish the best care I knew.

Don't panic. Comet obviously had an existing problem when you got her. You can't know eveything when you're starting up and you are obviously VERY diligent so don't go feeling guilty.
Let's wait for Jen or someone on what to do with the UG Filter. If the other fish is OK there's no immediate panic for now.

Waiting for the ug verdict.

Dont feel bad about doing something wrong. We have all been new at this sometime or another and we all have done something wrong while in the learnig process. I had 5 goldfish and 30 guppies in a 30 gallon tank when i started. we all make mistakes

Thanks, I feel better. Who would think that the people at the pet store would mislead a new buyer??? I just trusted what they said. After all I wanted the best for my 2 goldies, and I did not know of this site 2 years ago!!

petstore employees most of the time dont know much of anyhting about fish. they are just there to make some money and to sell you stuff you dont need. Its very common to think that just because someone works at a petstore, they know alot about pets, when really that is not true.
In fact there was a thread a while back that was about stupid things petstore employees say. I remember one where an employee told someone that the pearlscales were puffer fish.

Now I know better than to believe them.

So should I remove the UG filter from the tank. If so what is the best way to do it without messing up the cycle too much??

One thing I'm unclear about;
is the other filter you mention already installed or were you thinking about getting it? If it's already in place, you just need to make sure it's had long enough to grow it's own bacteria before you deal with the UG, otherwise you'll have to cycle again.

As far as removing the UG, I'm hoping someone who has actually had to do it will help but.......

considering that the problem with UG's is their potential to accumulate harmful bacteria, I would want to remove the fish and the other filter while dismantling it. After you've chucked everything out and changed the water I guess you should put the filter back and leave it running for a while before replacing the fish. Perhaps some live bacteria like BioSpira would be good to have ready beforehand? Now I'm not sure if you should do something like run salt for a while or add anything to the water but maybe someone else can jump in? I've not ever had to do this so I'm not 100% sure of the correct proceedure.

Other input, please......


Sorry, just checked back and see you do have the other filter already.

Thanks Pixiefish! As you recommend I will wait to hear other input before I do this big job.