The sun is pretty harsh in Central Queensland and the problem that I keep facing with outdoor tanks are the algal blooms that take over and smother everything. I have been told that the aquaculture researchers at CQU say not to worry about this as it doesn’t affect the fish but I think that it looks appalling and can’t be good for the hygiene of the system. On one of the tanks I covered it with a wooden lid but this is not a good solution for the larger AP tanks so I played around with it until I got the following solution.
This tank was seeded with miniature Papyrus and duckweed. The duckweed covers the total surface except for and area over where the air bubbler is placed. The duckweed reduces evaporation and cuts down the amount of sunlight getting into the tank. Next I added a one off hit of barley straw extract to get the existing algae under control and finally I added a large number of Swordtails and Guppies that I got from Peter D and Bill M which are doing a really good job of cleaning up any new algae that forms.
This tank will be used as a redclaw growout tank but I see no reason why Jade and Silver perch can’t be added as they don’t tend to eat fish the size of swordtails.
The Miniature Papyrus is an excellent tank cover plant as you can spread it by just cutting a piece off and dropping it into a new location. The Papyrus forms a floating mat that gives the Swordtails babies plenty of room to develop and doesn’t take up space in the tank for the rest of the fish as it floats on the surface.