By Donna M. Recktenwalt
Put tree leaves in your tanks, you ask? Well, why not? Through experience, a number of killikeepers have found that the addition of oak and certain other leaves to their fish tanks has proven beneficial.
“Oak leaves are a useful addition to a killi setup,” says John De Luca. “What can be more natural than nature’s own tannins to acidify the water for Aphyosemions? … I have found that the quantity of leaves doesn’t matter as long as the pH will not drop below 6.3.” Quality of the leaves is another important factor. “Use only leaves that have fallen from the tree when they are brown,” John cautions, “and make certain that no animals have fouled the ground they lie on. You can also try beech leaves, which seem to last longer.”
“I use whole oak leaves a lot,” says Ted Klotz. “It does help to acidify the water somewhat and also gives the water a nice amber coloration. In addition, it gives the fish a place to hide. Most Aphyosemions are shy and need as many places to hide as you can provide. Most Aphyosemions come from streams where leaf litter is quite common, so it makes them feel a little more at home. It seems to me that the more ‘cluttered’ [the tank is] with leaves, java moss, mops, etc., the more you see the fish. Leave the front clear and they’ll honestly come out and see you once in a while.”
“I don’t boil the leaves,” Ted says. “I usually pick them up off the ground in the fall when they’re dry. I store them in a grocery bag and whenever I set up a new tank I add a few. They float for a few days and then sink. The only problem they present is clogging the intake when you’re siphoning off mulm, but the benefits far outweigh the detrements.” Collected in the fall and stored dry in mesh or paper bags, oak leaves will keep for a year.
Other leaves have also been successfully used by aquarists.
“I use the leaves of Terminalia catappa, the tropical almond, for the same purpose,” reports Ramon De La Cuetara, who lives in Puerto Rico. “According to a betta breeder in Singapore, the tannins have antimicrobial activity, in addition to acidification and coloring the water.”
“I have used grape leaves in the past,” says Bruce Bernard. “Many wine making supply houses carry grape tannin processes from the skins of grapes. It takes about 100 mg. to 10 gallons to give the water a rich hue. Very potent!”
Of course, in time leaves will decompose, producing litter. Put the leaves in “nylon sacks (found at fish stores or made from old nylons) with a rock in the bottom, and place them in the tank (or filter) where there is a good flow,” suggests B ruce Bernard. “This will keep them from littering the whole tank. I also do this in water I age, using one large nylon sack and just transferring it between containers.”
As the vegetation breaks up, infusorians flourish, giving the fish (especially fry) an additional food source. “Oak leaves [also] help daphnia,” points out Ted Klotz. “M y favorite [collecting] spot has many oak and beech leaves as a substrate.”
One type of leaf to not use is maple. “All us ‘old-timers’ know that maple leaves won’t work,” says Lowell Patrick. Dick Martino agrees. “I would be very hesitant about using maple leaves,” he cautions. “They contain certain phenolic compounds which could cause some problems, and they do not decompose very well.”
– G.C.K.A. Newsletter, August 1999