Can you advise me on a still-water garden pond in tropical Central America?

Question

We're looking at making our first backyard pond in the edge of our garden. I have read a LOT of pages through searching on Google and they seem to make it so hard to get started. I don't think it's this hard so I need some advice.

Our pond is going to be sort of round, mostly. Then it will elongate the last part maybe 3 to 4 feet long under our walkway as a mini under the bridge type deal. The round part of the pond will only be 4 to 6 feet in circumference. So a very small pond really.

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• First thing is can I just use either the dirt itself as the liner or line it with lime? (Lime: From what I have read through articles I have found, helps starting a pond with pH levels, bacteria, etc.) We live in Guatemala in Central America so pond liners are not easy to find, I would have to import it and that gets expensive, no point in it.

• We live in the tropics, so no need for worries of freezing or anything of the sorts. The temperature is normally from 70°F to 90°F with no humidity, very nice all day long and all year long. Rainy season is a bit wild, but only 4 months long, just a lot of rain during those months.

What kind of fish would be good for this size of a pond and climate? I love Koi but they seem very work intensive and take a lot from what I have read. But I don't believe everything I read as the McDonalds down the road has Koi outside in a small around the building pond made of cement, so they can't be that big of a pain ha ha.

Or would Goldfish be better? That being said how many would be the max of a given fish, or better yet a good number of them?

• I do "not" want a filter and a bunch of pumps etc. in our pond. I would like to have a still water pond. I know it will be a bit muggy, that's fine mostly as it won't be horribly deep in the elongated part under the walkway.

  That being said, what are the suggestions for still water ponds to keep them clearer? Can we not buy a couple bottom sucker fish for it? We had one in our fish tank years ago that grew to 7 inches long.

  Or is there another fish to keep them clean?

  Are there some plants that would be suggested as water plants to help keep it clear water?

• Would turtles be good to have to help keep it clean?

• What do the fish eat? I know that for aquarium fish you get fish food, but wouldn't the mosquito larvae (a lot during rainy season as I had Tilapia tanks once) and other natural things be good food for the fish?

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We really want this pond to be 100% natural and still without mechanics of any sorts. Electricity is hugely expensive in Guatemala, so we don't want pumps running year round.

Any other advice that can be given would be greatly appreciated for a first timer.

Answer 1

I'm not sure you can have everything you want with this project. While this is not a complete answer you may find some of these points to be relevant:

• turtles eat fish, frogs and just about anything they can ambush. Not a good mix with many other animals.
• if you want a still pond you will have an ideal environment for mosquitoes. If you think a few more won't hurt then you could stock the pond with fish that will eat the larvae. I am sure there are local fish species that would rise to the challenge.
• in order to compare lime vs pond liner you should check out other ponds in the area. Pond liners are good for at least 25 years. Subsidence in the earth or earthquakes could easily cause leaks in a compacted lime liner. If you want this to last then use 40 or 60 mil food grade pond liner.
• once you have a pond you want a bigger one. Why not go big now? The larger the pond the more stable an ecosystem it can have
• sadly you are not building an ecosystem that can thrive without external inputs. It is more like a watery compost heap. Let me expand on that:
  • plants absorb the nitrogen that fish and turtles excrete. If they are not present then algae will be happy to make your pond into a green soup
  • decaying plant material releases nitrogen. Every leaf that settles to the bottom of the pond slowly decomposes and releases nitrogen. Even potting a plant in topsoil and putting it in the water releases nitrogen.
  • algae! More than an aesthetic problem they can fill the top six inches of the pond and choke out plants. It does provide some cover for fish fry so some is good. Algae thrives in conditions where plants will just get by.
  • oxygen levels: still water does not absorb as much as moving water. Low oxygen levels mean only tougher fish can survive at the top of the pond.
  • it is a good practice to remove the sludge that accumulates in the bottom of the tank. Sophisticated designs use a pond liner and a bottom drain. Or you can vacuum your pond yearly with hobbyist tools.
  • without a filter sludge will accumulate faster and nitrogen levels will be hard to maintain at a stable level
• koi: they are like watery lawnmowers. They will eat other fish, plants and anything that will fit in their mouths. They need better water quality than goldfish.
• goldfish: just as hungry as koi but no regrets if they die.
• if you have fish eating birds in your area they will visit your pond and eat the most expensive fish first.
• keep in mind that fish like a variety of depths to live in and more water plants can be found that need to sit six to twelve inches underwater. You need ledges for the plants.
• you need to have a stable edge for the pond. People like to walk up to the edge and look in. If their weight collapses the edge and they fall in.....
• what are the local laws about ponds and pools? Where I live if you can drown in it you have to fence around it.
• there is one way to have a still pond that does not need a filter or a pump or much maintenance. Just add some bleach. How much depends on the volume in the pond but doing this would ensure no algae or mosquitoes. However you could not have plants or fish. You could start with 1 - 2 mg/litre

Answer 2

You can have most of what you want but it will cost you in space. I would look into natural pools The water will be filtered by the plants taking up the nutrients. They are also somewhat low maintenance depending on what plants you and fish you put in.

• I disagree with kevinsky that turtles will eat fish. It will depend on what type of turtle you get. Birds will not eat your fish depending on the size of fish you get.
• you can choose from pond liner or concrete and cement. If you have natural dirt you have to check if any problems will occur when the water seeps into the ground.

• To clear mosquitos Gambusia species is a common choice for their low maintenance. Dragon fly larvae and frogs will also eat mosquito.

• For fish you have to determine how deep your pond is, if it is too shallow the water will heat up too quickly before it can be cooled off and your fish will cook in the high temperatures. Secondly you have to limit the amount of fish you have if you want to do not want a pump or the water to be cloudy.

• Since there are no filters you will need lots of water plants see here Lava rock and coarse gravel can serve as a bedding area for these plants. The Plants will absorb phosphorus and nitrogen which can cause growth of algae. You will have to trim and divide them every so often but the rate they absorb is faster than the rate decaying plants can release nitrogen to cloud the water.