Q. I have two blue gouramis, two gold gouramis, and three cory catfish in a 10-gallon tank. Also in the tank are four plant specimens. The plants are jungle and corkscrew Vallisneria. The plants have slowly shrunk in height over the past two weeks (I have only had this setup for about two and a half weeks). The gravel size is one-eighth inch diameter and is brown, and it is about 11/2 inches from the bottom of the tank. Ammonia and nitrite levels are low, and the pH is 6.6. The filter has become clogged with plant debris.
How can I stop the plants from becoming short? Are the gouramis and cories eating them? If so, how can I stop this? Is there anything that I should add to help the plants grow? Does the pH need to be adjusted?
-- Gregg Zolla
A. There is nothing wrong with your pH as far as the plants are concerned. However, there are a few points are worth mentioning. Unless you are adding carbon dioxide to the water (adding carbon dioxide tends to lower the pH), your pH indicates that there is very little carbonate in the water. Vals are one of the few plants that can get carbon from carbonates besides getting it from CO2. If everything else is in good order, your plants might benefit from higher carbonate content in the water. You might try adding some calcium carbonate or baking soda (sodium bicarbonate). You can get calcium carbonate from some nurseries, from web vendors that deal in hydroponic gardening and from brew-your-own-wine/beer web stores. About three-fourths of a teaspoon baking soda per 10 gallons of water will increase the carbonate hardness (KH) by 4 degrees and will not increase general hardness (GH). About 11/2 teaspoons of calcium carbonate per 10 gallons of water will increase both the KH and the GH by 4 degrees. If you want to get fancy, you can use some of each in proportion to adjust the KH and GH to desired values. I would add about three-fourths to 1 teaspoon of baking soda or 11/2 to 2 teaspoons of calcium carbonate in your case to get the KH up to roughly 4 or 5. If you do 50-percent water changes each week - always a good idea - add back half those amounts with the new water, adjusting as needed to maintain roughly 4 or 5 degrees KH. You can get a KH test kit from the local fish store. They are inexpensive and easy to use.
However, from what you have written, I do not think increased carbonates alone will solve your problem. My guess is that your plants are undernourished. This always leads to stunted growth and eventually a premature end. As the live plant mass dies back, the detritus ends up on the substrate and in the filter. Look through my previous columns on the FishChannel website; you should find enough information to restore your plants. In particular, take a look at the sections about nutrients:
A Stable Plant Tank
Q. I have a 29-gallon community tank with two clown loaches, two mollies, two catfish and two tetras. I have had them for about 6 months, and they are doing well. My problem is that I cannot get live plants to grow in my tank. I have tried several different types (several banana plants), but they all just lose their leaves and rot away. The PH is about 7.2. Nitrite is ok, and water hardness is about 10. I use plant food every week and bought a new plant light, but I have had no luck. I really would like to have live plants; it makes it so much more real. Please help.
-- Bobby Stone
Henderson, Ky.
A. You say your fish have been doing well for about six months, and that indicates that your aquarium is in a stable condition. However, a stable and healthy condition for fish will not necessarily mean that conditions are good for plants. I am guessing that the clown loaches are very young. Eventually, they will grow much too large for a 29-gallon aquarium, but it will take several years. You do not have many fish in the aquarium, so fish food is probably not supplying adequate nutrients for plant growth. There is nothing wrong with having a light fish load in an aquarium, but supplementing with additional plant nutrients is a good idea. You do not say what plant food you are using, but you probably need to add all the macronutrients, potassium, phosphate and nitrate, as well as trace elements from a good trace mix.
Aside from general nutrient issues, aquatic gardening takes a bit of a knack to grow the more demanding, temperamental plants. Banana plants (Nymphoides aquatica) prove difficult for many folks, so I suggest you forgo them and try some easier plants. There are slow and fast-growing plants that are easy to grow. The slower-growing plants will more easily adapt to a moderately lit (less than 2 watts per gallon) aquarium with low levels of nutrients.
Among the slower-growing plants, you might try Anubias barteri var nana. This dark green plant with short stems and cardioid-shaped leaves does well in a moderately lit aquarium or when shaded in a brightly lit aquarium. It can be grown attached to rocks or driftwood, or it can be placed on the substrate. Because it grows very slowly, it does not demand a lot of nutrients; on the other hand, the older leaves can begin to show algae in a few months. These can be pruned by peeling back and pulling the stem away from the base.
Another slow-growing, relatively undemanding plant is Java fern (Microsorum pteropus, sometimes mistakenly written as "Microsorium"). This deep dark green, leafy plant is hardy and tenacious. The leaves tend to be long, narrow and flat, with noticeable veins. The leaves sometimes develop into two or three lobes, but this seems to happen mostly on plants that have been allowed to grow large. If water conditions should take an undesirable turn, Java fern will not wither and shrink overnight; it is a very forgiving plant. It does well in temperatures from 65 degrees Fahrenheit to 85 to 90 degrees. Although you can grow it in a brightly lit aquarium with two watts or more per gallon of light, you can grow it more slowly in aquaria with only 1 to 1 1/2 watts per gallon of light. The plant does not seem especially tasty to fish, and herbivores generally leave it alone. It is equally tolerant of how acidic/basic your waters is, accepting pH values from 5 to 8, and the water may be hard or soft.
Java fern does not grow in the soil or planted down in the substrate. It naturally occurs clinging to the rocks behind, under or near waterfalls, where the fine mist from the falls keeps the plants wet, and the plants can find cracks and crevices in which to lodge themselves. It also grows along the water's edge in mountain streams, attached to rocks and roots. Beside streams, Java fern may be submerged in the rainy season as the stream rises on the banks. The roots of these plants "glue" themselves to other roots, rocks or driftwood. You have to tear them free if you want to move or remove them. Since the Java Fern does not root in soil, they get all of their nutrients from the water and air. Note that besides growing immersed (with part of the plant out of water), Java fern also grows submerged, a condition it naturally withstands during the rainy season when streams overflow their banks.
To add Java fern to your aquascape, attach it to any rock or piece of driftwood with a cotton thread or rubber band. By the time the rubber band dissolves in a few weeks, or the thread dissolves in a few months, the Java fern will have taken a firm hold on its own. You can also mimic nature by snagging the rhizome of some of the roots in cracks and crevasses of rocks and driftwood.
Java fern grows along a rhizome, which is a sturdy stemlike structure that sends up leaves along its length. Mature leaves develop small, dark, spore-producing spots on their undersides. Besides spores, Java fern propagates by adventitious budding that occurs on the edges of mature leaves. You can easily break these new baby plants off and grow them into adult plants. If some pieces of leaves are broken off and left floating in the aquarium, they will probably develop baby plants. In addition, if you do not trim back the baby plantlets, they will eventually break free on their own, move along in the water current until they snag on some object and begin growing at the new site, just as in nature.
You can prune Java fern by cutting the rhizome to divide a plant. You also can prune by snipping the leaves. Even if you cut back the leaves rather severely, the plant will just grow plantlets from the leaf edges and grow new leaves. For a while, the cut leaves will show a crew-cut appearance, but the plant will grow out of that.
Anubias and Java fern are both often available in local fish stores. However, if you cannot find them locally, one or more varieties are usually available at the web stores.
Some folks will set up an aquarium with only Java fern. I like to have at least one fast-growing plant in an aquarium to help soak up any excess nitrates or phosphates. I think that most local fish stores that sell plants will have the Amazon sword (Echinodorus bleheri). This plant is very hardy and tolerant of water conditions, but it likes to have plenty of nutrients. It enjoys a lot of light and added CO2. Given a strong supply of these, an Amazon sword can grow large quickly. Yet, given less of any of these, and it will grow very slowly and remain small for a long time. If it begins to grow too large, you can prune away outer leaves by holding the stem as close to the base as possible, and peeling back and pulling away. Unlike Java fern and Anubias, the sword needs its roots in the substrate, with the crown of the base just at or just above the top of the substrate.
Another fast-growing plant that is easy to grow is water sprite, which comes in two commonly available forms: Ceratopteris thalictroides and C. cornuta. Either might be presented under the common name of water sprite. The leaves of C. cornuta are broader and rounder than C. thalictroides. There are differences in growth characteristics, too. You can grow C. thalictroides submerged with the roots buried in the substrate, while C. cornuta prefers to be a floating plant. Both plants grow quickly when given plenty of nutrients and light, but they do well at a slower place with lower levels of light and nutrients. Ceratopteris. cornuta grows especially quickly, in part because as a floating plant, it can get plenty of CO2 from the air.
You can prune either species of water sprite easily by snipping stems pretty much as you please. Moreover, the trimmings, if left floating, will develop new plants.
With these plants, you should find it easy to turn your aquarium into a lush, full garden. Once you do that, start trying other more difficult plants. You will find that some of the more demanding plants will seem easier than others, and what is easy for one gardener isn't always easy for another - water conditions and maintenance routines vary, and so do results.
So experiment. Try a new plant now and then, and find what fits your style, what seems to do well in your aquaria. A great way to share information and share the fun is to join a experience can benefit all of the other members. You can probably find a local aquatic plant club in your area by searching the web. Think globally, too. Another great source of info is the Aquatic Gardeners Association (AGA), a nonprofit organization of aquatic plant enthusiasts from all over the world, which appeals to both beginners and experienced hobbyists alike. Also, at that website you can see what some other aquatic gardeners, including beginners, have accomplished.