uncared for tank
 

my friend came over and saw my tank and the things i do to care for it. he said he had a 10g with 2 goldfish, 1 pleco, 1 molly. i know, i already gave him the speech and hes going to get a 55g in two weeks. but the problem is his tank has been in sunlight and has had no water changes in 9 months!!! i grabbed him by the ear and we went to his house. of course theres algae and the water was pretty clean. i did a 6g water change/gravel vaccum. it was bad in the gravel. we moved the tank out of the sun and did water change daily for next 3 days. i tested with a tetra laborett and all is good. should i do anything to remove the small amount of algae? since the fish appeared healthy i assume the bacteria are established. hes changing the filter today, is there any reason i shouldnt put his old filter in my 3 week old tank to help with cycling?

There is pretty much not a single thing correct about that tank...

Goldfish need cooler water and get far too big for that tank.
Plecos get far too big for that tank, unless it is a very small variety.
Molly's get too big for that tank.

At 9 months it's cycled, that's usually completed in under 2 months. If you put that tanks filter on yours, yes it will help it's cycle along but it would be needed on the 55 gallon to get its cycle going.

If this person didn't clean the tank in 9 months ... are they going to do the same with a 55 gallon? Even with that tank, they can't keep that combination of fish.

First on the algae, it is fine. Good in fact. Presumably there are no live plants, so algae is performing the similar task of using ammoinia and nutrients and producing oxygen, though minimally compared to a tank of plants.

On the filter to your tank, absolutely never do this. Even if the other person's tank "appears" healthy, it is undoubtedly carrying pathogens that you may not want. And with this present tank's state, I would be very careful not to transmit any wet objects from it to your tank. Fish can themselves not show disease but still carry it, and many diseases can be transferred by anything wet--including the aquarist's hands.

Good for you for helping! And, kudos to your friend for accepting your help.

Algae, in moderation, is not a bad thing - i would not worry about it.

As for changing the filter - what does that mean?

Yes, you could put it in your tank to get an instant cycle, but I hope that's not at the expense of your friends biological filtration.

hes going to do right by the tank, ill make sure. he really had no idea so he just needs good habits. what do you suggest he does to get stocked correctly? if i use his filter until he gets his bigger tank, will his filter still be helpful in his new one?

I don't understand what you mean by use his filter. The media, or the actual filter?

I agree with Byron, I would not use such stuff from poorly maintained tanks.

thanks . no filter change .i hadnt thought of pathogens. thank to all who helped.

I wouldn't take in fish from such tanks, either, but maybe that's just me.

Unless he only wants to keep goldfish, I would find a new home for them. The cooler water they require really limits the choices.

For the rest, it depends on a lot (pH, GH, KH). I would most certainly use hardy species, and go really light on the stocking until they get a solid habit of weekly water changes. They'll need a Python or equivalent. Bucket brigade on a 55 gallon every week will be a major deterrent to proper care.

There are plenty of fish that can be kept with goldfish.