Kater Kater
  • Just popping in
  • Just popping in
  • Joined: 4/7/2009 12:01
  • From Cornwall
  • Group: Registered Users Basic Membership
  • Posts: 14
  • Posted on: 1/6/2010 11:48
Is this too many please ? #1
We have two ponds, now 18 months old and looking really good with loads of plants and good water quality . The larger one, about 1500 litre , flows into the smaller 750 one via a waterfall , we have two filters and all is well . However, the 5 fish we started off with have bred like rabbits, and surprisingly, lots survived ! We now have the orignal gang of five ( about 4 inches in length ) and a mix of goldfish and commets , plus about 25 of their offspring, ranging from an inch to two inches in size, plus another 12 in the smaller pond . Just a little worried in case this is too many fish ? They all apear to be doing well , even the bronze carp are changing colour to reds and oranges and many are really beautiful multi coloured fish, thanks for any advice , we dont want a third pond !
Otter Otter
  • Just can't stay away
  • Just can't stay away
  • Joined: 30/10/2007 6:54
  • From United States
  • Group: Registered Users Basic Membership
  • Posts: 100
  • Posted on: 3/6/2010 10:34
Re: Is this too many please ? #2
The usual rule of thumb for goldfish is 30-50 gallons per adult goldfish. The requirements for a fish go up roughly with the square of length, hence four 5-6" fish roughly equal one full-grown fish, but of course they'll keep growing. I think you're likely to start having problems as your fish grow. And if they continue to reproduce successfully, you're looking at a Malthusian crash.

Besides finding a new home for some of your fish and/or building a bigger pond, you might want to think about adding a predator to eat the eggs and fry. Here in the US, ponders often use sunfish for this purpose, being careful to have only one fish, fish of all one sex, or less fertile hybrids, lest the sunfish themselves overpopulate. I wouldn't recommend these fish outside of their native range, but I'm sure you have something over there that could do the job.
fredrick_more fredrick_more
  • Pond Moderator
  • Pond Moderator
  • Joined: 4/3/2005 17:50
  • From Nottinghamshire
  • Group: Registered Users Caresheets FK Supporter
  • Posts: 3171
  • Posted on: 10/6/2010 20:05
Re: Is this too many please ? #3
Not without eating the other fish

With Goldfish its a matter of reducing numbers every now and then unfortuntly.