make a concrete pond shallower

[Sainty1]

We have had this pond for about 30 years and most of that time have had to get fish from others to keep it restocked. We don't seem to be able to breed many of our own fish. I think it is because the pond is too deep 1/2 of it would be about 50cm to 80cm deep. The shallower area down to about 40cm and there is an island in the middle of this circular pond. the fish we have are healthy and the pool is clear and healthy. but cats, birds etc seem to keep the numbers down. So we have emptied the pond and put the fish into another small pond while we decide what to do. It has been suggested the pond is too deep and that is why the fish don't breed so we could fill it with a couple of metres of small pebbles to raise the level ? Any suggestions appreciated

 

[Mmathis]

Hello and welcome. Thirty years — that’s an old pond!

What kind of fish do you keep? If my calculations are correct, the deepest point in your pond is only about 2-1/2 feet deep — which is a good depth for things like goldfish. But, also with the shallower parts, it also sounds like it would be easy access for predators. So, I guess maybe I’m not understanding the whole picture. What makes you think it’s too deep? And that this depth is inhibiting breeding? If you make it any shallower, it seems like it would be even easier for predators to get your fish. Maybe that’s why your fish never breed — the predators are getting them. How many gallons is your pond?

Please give us some more information about your pond.

 

[Sainty1]

View attachment 115965 View attachment 115966 We have had this pond for about 30 years and most of that time have had to get fish from others to keep it restocked. We don't seem to be able to breed many of our own fish. I think it is because the pond is too deep 1/2 of it would be about 50cm to 80cm deep. The shallower area down to about 40cm and there is an island in the middle of this circular pond. the fish we have are healthy and the pool is clear and healthy. but cats, birds etc seem to keep the numbers down. So we have emptied the pond and put the fish into another small pond while we decide what to do. It has been suggested the pond is too deep and that is why the fish don't breed so we could fill it with a couple of metres of small pebbles to raise the level ? Any suggestions appreciated

View attachment 115965 View attachment 115966 We have had this pond for about 30 years and most of that time have had to get fish from others to keep it restocked. We don't seem to be able to breed many of our own fish. I think it is because the pond is too deep 1/2 of it would be about 50cm to 80cm deep. The shallower area down to about 40cm and there is an island in the middle of this circular pond. the fish we have are healthy and the pool is clear and healthy. but cats, birds etc seem to keep the numbers down. So we have emptied the pond and put the fish into another small pond while we decide what to do. It has been suggested the pond is too deep and that is why the fish don't breed so we could fill it with a couple of metres of small pebbles to raise the level ? Any suggestions appreciated

 

[Sainty1]

The pool is about 1,000 gallons . We had netting over it during the last breeding season and got maybe 10 little fish. We have about 40 fish in the pond. Ranging from 2" long to 9". We only think it is the depth that is maybe making the pool too cool and the fish aren't breeding because 3 friends with shallow pools about 1 ft breed more fish than they can use and give them away. We want to breed our own. We have both male and female fish and see them spawning. I don't seem to be able to see the eggs to transfer these to a different pond. I have put rope and various other things to try to get the eggs to stick on there.

 

[sissy]

40 fish in 1000 gallons is over stocked .Most fish if hungry will eat the babies or the eggs so that could be more the reason for not seeing many baby fish

 

[Mmathis]

@Sainty1 Did I miss what kind of fish you have? And do you have any kind of media in the pond for the fish to spawn in — something like plants or a spawning mop? If there is nothing for the fish to spawn in and nothing for the eggs and fry to “hide” in, the eggs are going to be eaten by the adult fish. Fish eggs are a delicacy!

 

[j.w]

@Sainty1

 

[addy1]

Welcome to our group. Your fish are probably eating the eggs and babies.

My pond is around 5.5 feet (152cm) deep, I get fry, do my best to the eggs eaten to keep down the numbers.

 

[Lisak1]

Welcome @Sainty1 ! I agree - 40 fish is a lot for 1000 gallons. They are naturally keeping your population down I would guess. I bet if you "thinned the herd" you would start to have more babies surviving. Your pond is definitely not too deep - and I'm not even sure how that would work... fish breed in lakes and oceans, right? Much deeper than your pond.

Whatever you do, don't add that many small stones in the bottom. A shallow layer of gravel is beneficial; too much gravel can be deadly as it will collect too much gunk and debris. Not a healthy situation for a garden pond.

 

[Tara]

I have put rope and various other things to try to get the eggs to stick on there.

Have you tried underwater plants for spawning? Maybe it might help a little.

 

[Sainty1]

Hi thanks for all the replies sorry I have been away for a couple of days so haven't replied. I must have worked out the amount of water incorrectly as when I look in the pool usually you can only see about 10 fish at a time. these fish range in size from 1" to about 6" . We haven't seen another pond as big as ours. It was made for koi but these died after about 25years and they are illegal to own in NZ now. I do have several types of oxygen weed plus asparagus weed and 5 large water lillies.. I feed the fish a little each day during the summer and less in the winter. They seem to grow well until the herons fly in and have a feed. I do have another smaller pool so I think one of the females looks pregnant so should I keep her in this pond with a couple of males and leave the other fish in the large pond is that a good idea??

 

[Mmathis]

Maybe you should consider putting a net over your pond! Several on here have resorted to that method and it seems to be foolproof at keeping the GBH’s away from the fish!

 

[Sainty1]

Maybe you should consider putting a net over your pond! Several on here have resorted to that method and it seems to be foolproof at keeping the GBH’s away from the fish!

Thanks for the info Turtle Mommy i have just got somebody else to measure the water content and it is about 3,000 gals. I have decided not to make it shallower. I will give it another try with a net over the top and read up n how to take the eggs out into a pond with no fish in it. is that a good idea???? I do appreciate all of the advice. We love the fish and used to have lots of them but never many babies.

 

[WhiteNoise]

Keep the fish fed properly, set up an area in a more shallow part of the pond and place some rocks across it like a damn but under the water with gaps for little fish and the ones that survive will congregate there for safety.

That is how I have one of my ponds set up and I have well over a hundred babies survive last year and another 30 this season. (This season I opened up the rocks hoping to not have as many babies and it worked.)

I actually built a smaller pond to transfer the babies to.