Very large but flat Tank a good idea ?

[Yvonnes]

Hello

I am new here and have a question
I want to have an indoor pond in my house for freshwater.
The measurements are 5 meters (16.4 feet) by 2.5 meters (8.2 feet) and around 40 cm (1.3 feet) high (or 30 cm maybe). I am just in the absolute beginning of planning and of course I will inform myself about the requirements of the fish I put there first. Do you think this would be a good size for different types of fish ? Or is it too low for most ? The evaporation and cost for setup and maintenance is not something I need advice for since I have it already figured out. I want to put many plants in and just a few fish. All freshwater and just small fish and shrimp , no fancy fish. I also do not care how the fish look or if I can see them ( they can be hiding in the plants). And regarding an extra question is this height ok for discus fish ? I saw that they are often housed in tanks that are lower, but I would like to know if they would be really happy with 1.3 feet height. And I know discus fish should not be kept by beginners... thats why I would not put any there in the first few years. Just want to know for the future ( and maybe adjust the size already before... This is something that I would start in 2 month and I put the fish in only once I know enough , so don`t worry I am not gonna rush it. Thanks so much already to anybody answering

 

[Colin_T]

Hi and welcome to the forum

Lucky you getting to build an indoor pond. They are great if done properly but can be an issue in damp climates because they add extra moisture to the air and encourage mould.

With most ponds, the water level is usually 4-6 inches below the top of the pond, so if you want 2 foot of water, you build the pond 2.5 feet high.

Most fish do best when the water is at least 18 inches high and preferably higher (2-3ft).

Discus need the water to be at least 2 feet high, and 3 feet high is better. Discus can grow to 10 inches in diameter so the higher the pond, the more room they will have.

Discus aren't that hard to keep if you know the secret. It is in the link below (every discus keeper should read it) and has to do with their diet. They are primarily vegetarian and have all sorts of intestinal issues when fed a meat based diet. They should be kept in well planted tanks/ ponds that also has algae growing in it. Then they are easy to keep.
https://moam.info/the-discus-fish-symphysodon-scielo_59c411371723ddc7f4532afc.html


*NB* If you have young children, you should fence the pond off with a pool fence so they can't fall in.


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Do you live in a warm climate?
If not, you might have an expensive heating bill with a large open pond. You can insulate the surface with bubblewrap. Just leave a 1 foot diameter section open and cover the rest of the pond. The bubblewrap floats and helps insulate the water. It also reduces evaporation.

You can insulate the base and sides of the pond when it is being built. This will help stabilise the temperature and reduce sudden fluctuations.


Skylights in the roof can provide light for any plants and will significantly reduce power consumption. Most people have a few small lights that can turn on in the evening and let the skylights provide the majority of the light.


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What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

Depending on what the GH of your water is, will determine what fish you should keep.

Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

 

[Yvonnes]

Thank you Collin.

I did not expect such a nice and thorough reply
Thank you for all the tips.
I will keep them in mind while planning. I do not have kids, and it is warm where I live. I thought about putting a acrylic glass lid on top of the pond to have less humidity. The room is well ventilated the whole year. I am sure I will have ore questions in the future and I am so glad I found this forum. Thanks again and have a nice day.

Yvonne

 

[Colin_T]

You can use Perspex (acrylic) covers on the pond to reduce evaporation and trap heat but you will need a frame made up to support the covers because Perspex sags. So you would use smaller sheets (18-24 inches square) and use thicker acrylic (6mm thick) so it doesn't sag as much.

You can leave sections without the Perspex covers and let the marsh plants grow up and out through those open sections.

If you make the top edge of the pond 6-12 inches wide, you can sit on it and look at the fish while having a drink and chatting with friends.

 

[Yvonnes]

You can use Perspex (acrylic) covers on the pond to reduce evaporation and trap heat but you will need a frame made up to support the covers because Perspex sags. So you would use smaller sheets (18-24 inches square) and use thicker acrylic (6mm thick) so it doesn't sag as much.

You can leave sections without the Perspex covers and let the marsh plants grow up and out through those open sections.

If you make the top edge of the pond 6-12 inches wide, you can sit on it and look at the fish while having a drink and chatting with friends.

Thanks so much again That sounds like a great idea, I think that would look really good!
Sorry for replying so late. Probably there will be many more questions in the future, and I am so grateful for your ideas and explanations

 

[ColdKoi]

I agree a modular cover would be a pretty neat way to go. Leave a panel out here and there for plants to grow through while still holding in the majority of the moisture

I assume you’ve already thought this out well enough but please make sure that the floor it’s placed on is going to handle the weight. That tank is going to hold over 8000lb of water alone and even given its shallow depth and large appearing footprint, it’s well in excess of the 50lb/sqft most floors are designed to handle

Any thoughts on the filter setup? For something with that much area I think I would opt to use submersible equipment hidden in hardscape in opposite ends/corners to try and keep that water moving without over complicating it. If you’re keeping it fairly low bio load with just some small fish and shrimp you shouldn’t need a pile of filtration capacity, mores just to keep the water moving.

External canisters would be a great option too, but to achieve good water flow you probably have to have one at either end of the pond or have them both at one end with plumbing all the way to the opposite end. Obviously either scenario has it’s drawbacks, you need a cabinet or place for the equipment at both ends or you have to run the plumbing that distance and lose flow/efficiency

Best of both worlds would probably be a large canister filter at one end, then some submersible water pumps/wave makers to circulate water at the far ends of the pond


I’m picturing some small fish like a school of danio sized fish and a plethora of neocaridina shrimp. Low bio load and low maintenance (and the shrimp are going to reproduce for you easily to keep their numbers up). With only a foot or so of water column I don’t foresee a lot of fish being able to thrive in that. That’s not a lot of depth for a full grown fish to work with, without skimming the top or dragging bottom lol. A full grown discus would have a hard time in there as a good healthy one has been know to be 8-10” in height and even on the conservative end of 6” full grown that still really leaves no room for the fish to move vertically. I would stick with much smaller fish and more of them for sure

 

[Colin_T]

ColdKoi has brought up a good point about flooring. If the floor is reinforced concrete it should hold the weight without any issues, but if the floor is wood, it's a no deal.

Talking of filters, an internal water pump with a sponge could be used to pump water to an external trickle filter and the water could flow down a water fall. The trickle filter would live behind a waterfall type feature so it's hidden from view. Every month, you would clean the sponge on the intake of the water pump and the filter media in the trickle filter.

 

[Yvonnes]

Thank you Coldkoi and Collin for all the advice. I am so sorry I just reply now. I did not see you wrote (it was in my spam folder and I am so busy setting up everything and moving). I live in Europe and the house is build with stone and concrete, has no basement so I assumed it is ok regarding the weight. My cousin is an architect and also thinks it would be fine. Thanks for the input regarding the filters. My idea is also to keep just a few small fish in the beginning at least. I will build it a bit deeper to be more flexible in the future. My main interest is to offer a nice habitat for some fish, have them happy and I can enjoy the view Since I have parrots, I will cover the tank most of the time where they can go since otherwise, they poop inside... Regarding the shrimps , I love them, but I am worried they will reproduce like crazy. Is this an issue for people (because I don`t want any of them to suffer)
Thanks again soo much Coldkoi and collin.

 

[Colin_T]

You can have shrimp in a pond. They breed if there is lots of food for them. If you don't overfeed the fish, the shrimp shouldn't breed too much. If shrimp do breed, you can sell them to a pet shop and use the money to buy more fish.

A concrete and stone floor is fine.

 

[Yvonnes]

Hey Collin,

thanks. Good to know Extra money is always good.
Have a great day

 

[ColdKoi]

Depends on the shrimp you get. Something like bamboo shrimp or amano shrimp won’t be able to reproduce in freshwater. They’re also quite a bit larger and would better suit a pond in that sense, just more expensive and eventually you have to replace them when their time runs out whereas neocaridina should keep their population as long as the environment allows

Neocaridina (your typical cherry shrimp type) will definitely reproduce, but they shouldn’t overpopulate unless you’re drastically over feeding. Such is the case with any critter you put in there, if it can reproduce in the environment and they have an abundance of food then you can count on them multiplying!

Survival of the fittest and whatever the food source can sustain