[grinling]

When we moved, it turns out the 8' x 8' and 3' deep pond had a couple of fish in it about 10-12" long, either koi, goldfish or just carp. The filtration & pumping equipment was partly dismantled & we intended rehoming them & making a small nature pond out of it.
Over a couple of months, pond has gone greener, now brown and fish have been busy as there are seven 4" babies and they are all gulping at the surface. we were feeding them but understand this will encourage the algae which uses up oxygen. There are a few lilly plants in there.
Will we be OK just putting a fountain in until we find a home for them? They seemed to like pondwater sprinkled in with a watering can but can't stand there all day doing that!
Could we add tap water?
Help!!

[sunshineband]

They would be fine with a fountain, and will enjoy this.

Ours cluster under the outlet pipe from the filter like they are about to die if it is switched off.... but they are not, they just enjoy the oxygen rush I reckon 

Bear in mind that Koi are grown up in the far east in drainage ditches and thrive 

A cheap straightforward fountain run to splash in will do the job for now  and make sure that the water has enough oxygen for them.

Why is the water brown? is it very muddy?

[grinling]

My daughter and I noticed a little white fish 2 weeks back, so bought Koi food. We have not fed these fish and the last owner moved out in January. The water has been green until today when it looked brown. Don't know why it is brown.

[sunshineband]

It might be that the fish have stirred up mud from the bottom.

This might sound odd, but if the water smells OK, then it is not doing the fish any actual harm.

Just feed the fish the amount they will eat in about 5 minutes, so that there is no food left to rot at the bottom of the pond.

If the water is really disgusting, you can run a hose in the over flow it and this will (yes, make a mess  ) partiiall change the water. Don't put the hose nozzle at the bottom of the pond, but squirting across the surface of the water. The fish will love this, btw 

[grinling]

The pond isn't full, there is at least another foot or 2 available for water. Could I put tap water in, I am not water metered yet.

[sunshineband]

We use tapwater with no ill effects at all.

It will be mixed with the existing pond water so won't harm the fishs' slime coat

[Spana]

If the pond has been green and suddenly gone brown i would suspect the algae has died from lack of oxygen and the brownness is dead algae particles floating in the water.

[grinling]

Thanks for the replies. I have added more water, need to home the fish as pond too big, hopefully won't find one floating tomorrow.

[spottymint]

If the pond has been green and suddenly gone brown i would suspect the algae has died from lack of oxygen and the brownness is dead algae particles floating in the water.

Dying algae can deplete the oxygen also.

fish gulping at the top surgests oxygen depletion, splashing the water, water surface movement will help increse the oxygen.

Adding water will temp improve the oxygen level.