That depends on your pond. Most refuges are large enough for several fish at a time. Those are mostly overhangs in 12 to 20 inches of water. Sections of 4 to 6 inch flexible pipe works. It should be at least 18 inches long. Ceramic pipe works and cracked pieces are available at less cost. Large slabs of rock laid on top of cement block are good. Fish can hide in the most amazing places. You would never believe how many can crowd into a section of pipe. Large pots with a hole in them or placed on their side work. Plastic pots need a brick in them to make them stay in place. I don't recommend plastic crates. I have lost fish who get stuck and injured on sharp edges. They don't seem to realize they have grown too large or they forget in their panic or excitement. There are lots of different ways to make a hiding place. I'm sure other posters have much better suggestions. I'm not feeling too sharp today. Why don't you start a new thread on the subject?

Lindyip, I build a lot of koi ponds and I will share with you what I have learned over the last twenty years. First with your concern about Herons. Keeping the fish safe from heron is something that can't be guaranteed. But with the right design the risk can be cut down. A deep drop from the edge of the pond is the first step. It has to be at least 2 ft down to the first flat area. Deeper is better and I prefer at least 3 ft. But this is just the first step. The next thing that needs to be addressed is the pond edging. The last thing you want around the pond is flat surfaces that the heron can stand on. The heron will just stand on the edge and wait for fish to come by. I prefer to use round rocks that start in the water 8 to 10" under the water and protrude out of the water and over the edge. I have built koi ponds less then a mile from heron rookeries with no problems. My own koi pond I know gets visited by heron but I have never lost a fish in it to a heron yet my smaller garden pond a 100 ft away the heron get the fish all the time. The koi pond has been there for the 19 years. Next I would suggest a bare liner with at least two bottom drains. The last thing you want to have to do is to empty the pond to clean it. Not because of the work involved but because it will destroy the bacteria that it take a very long time to grow. As far as a UV light it will depend on how patience you are. For the first few years you will have problems with green water and string algae but after about four years the pond will take care of itself as far as algae goes. That is how long it takes to grow the bacteria that will take care of the algae. But those first few years the pond can be out of control. Mike

First off you only need to de-chlorinate the water when you add new water. If the water has been in the pond for 6 weeks the chlorine has long since dissipated. The green water is just unsightly to you and not harmful to the fish. Pleco's won't do a thing to clear green water. They graze on the algae that grows on the surface of the pond liner and other things that are in the pond. The green water is caused by single cell free floating algae. It's normally caused by water rich in nitrogen. You can help control single cell algae by putting plants in your pond to use up the nitrogen. You can also add some shade to help. Algae will thrive in bright light. As for your fish, I'd say don't fret too much. Fish will often hide for several days or more when moved to a new environment. If you are putting food into the pond and it's not being eaten make sure you remove it. Not doing so will contribute to the algae problem. Just visit the pond frequently and maybe just sit around for awhile. When the fish understand you are not going to harm them they will start coming up to visit with you. Oh and I forgot to mention that a UV light is often used to control free algae. You can get one from a pond store or online. Kinda pricey but worth it when you have algae issues. You have a very nice pond. I'm sure you will enjoy it once gets balanced

all my goldfish died this winter due to very cold snap pond froze over Iused the hose to keep water flowing. this was tap water .It worked last year but not this year was it possibly the cholrine in the water .