Anyone knows how to build a gravel/sand filter for a small garden pond with a pair of Oscars?

Answer 1

Sure and for a small pond with only a few fish you don't need a large or fancy set up. I assume you mean a wet/dry style instead of a fluid style. First, you will need to decide where to place the filter unit and how to return water to the pond. I would suggest placing it so that a small pipe will return the water either to a water fall or allow it to splash just a bit returning to the pond.

As for building the filter the only thing that might trip you up is the need for a very fine plastic filter cloth. Something that will not allow the sand to pass through. One possibility os Micron screening sold buy aquaculture suppliers and biological supply companies. Something around 10 microns would be fine. You can also use you imagination and try to find a good substitute. I have done this type of filter in a 5 gallon bucket before and it always has worked out very well.
Materials: Plastic bucket with a snap top lid and best to have flat sides. Check with a pizza place for buckets toppings come in, they are food safe and totally safe for fish.
2 bulkhead fittings for plastic hose.
submersible water pump large enough to move about 1/2 the volume of the pond each hour and with enough "head pressure" to lift the water from the bottom of the pond to the top of the filter.
plastic hose for drinking water the correct size to fit the water pump and the bulk head fittings. All of these are available at a decent hardware store.
Sand
Aquarium Gravel
several pieces of plastic mesh screening from the craft department of somewhere like Walmart.
PVC pipe to fit the inside of the bulkhead fitting.
Rigid plastic screening used in fluorescent light fixtures. Made like a grid with abut 1/2" holes. Standard stuff at most hardware stores or lighting supply stores.

Drill a hole in the side of the container near the bottom for the first bulkhead fitting. This will be the water outlet. Drill a hole near the top for the other bulkhead. This is the input. Cut a piece of PVC to span across the inside of the filter from the input fitting and drill holes all along the length. This will serve to spread the water as it flows into the filter. Cut most of the remaining PVC into circles that will lay in the bottom of the bucket. Place a piece of the rigid plastic screening over that cut a piece of the very fine filter cloth over the rigid plastic and come several inches up the sides of the bucket. add sand to this, about an inch will do. Put a few pieces of the mesh from the craft store over the sand ad a few inches of gravel over this and a few more pieces of the plastic mesh. I top mine off with a piece of air conditioner filter material. Just course plastic screening to get the largest stuff that flows in to the filter.

Now place the filter and attach the out put hose and direct it into the pond. Attach the hose and place the pump in the pond near the bottom. Run the hose from the pump to the top of the filter housing and attach it to the bulkhead fitting. Attcch your PVC to the inside of the bulkhead fitting. Fire up the pump and allow it to run long enough that you are sure it's not going to over flow. If it appear that it will, go back in and add a second outlet hose. Once it's running well snap on the cover. You can remove the top plastic and wash away the larger material trapped ther once every few weeks or so. Hope that helps give you some ideas. Feel free to write if I can help more.

MM

Answer 2

It sounds to me as if an indoor tank would be a better bet for you, up out of your brother's way, and with a lid on it. Anyway I don't think guppies would survive outdoors once the winter came. Terrapins need a heat lamp and a rock to bask on when small, and would probably eat the other creatures. Also they smell really bad because you have to feed them meat, which pollutes the water and decays fast under the heat lamp, and they grow really fast and then develop a nasty bite. People have been mistakenly releasing them into ponds and rivers once they're no longer little and pretty, and in some places they have grown to a dangerous size and upset the ecological balance. Trust me, my children tried it! A few days ago, a little boy died in his parent's garden pond, near to where I live. Don't risk it.

Answer 3

Wow! You want Oscars in a pond???? Make sure you tell your guests and everyone else to never stick their fingers in it. They like fingertips until they realize they can't swallow them... Other than that, I'd take the advice you already got and find some way to cover the pond with really small mesh if small children are about when you aren't. They aren' t Piranha, but the do have teeth!