To many people, an aquarium is not complete without live plants and most would agree that though artificial plants have come a long way, the beauty of a tank aquascaped with healthy live plants leaves no comparison.
1. Natural Water Filters
Live aquarium plants serve a real purpose in an aquarium. Plants are natural water filters consuming excess nitrates, helping to prevent various algae, which as simpler plants, tend to be starved out by the competition with higher order plants.
2. Refuge for Fish
We have already stated that a planted aquarium adds to the visual appeal of a tank, it also creates areas of refuge for the fish, thus providing security which in turn reduces fish stress.
Most Ichthyologists estimate that 80 – 90 percent of fish disease is caused by stress, therefore anything we can do to help reduce stress on all tank inhabitants improves our success rate at maintaining a healthy aquarium.
How to ensure the health of your aquarium plants
Make sure it is an aquarium plant
Based on my experience, the first step to insuring a plant will survive and thrive in a aquarium is to be sure that it’s supposed to be there.
If a plant looks suspiciously like a houseplant, it probably is.
For example, dwarf palm, various ferns, dumb cane (diffenbachia), arrowhead plants, corn plants (draceana), “red waffle” plants (also sold as “red crinkle”), polka dot plants, and spathephyllum (i.e. peace lily and antherium lily) are commonly sold in local pet shops for your tank. These are usually sold as potted plants.
If the store you are frequenting has knowledgeable and reputable sales staff, they should be able to tell you if a particular plant is truly an aquarium plant.
Though many of these plants will survive for a short while under water (a few months at most) they will eventually rot.
Make sure you have proper lighting
The next thing to consider when choosing a plant for you tank is the lighting requirements of the plant.
As a rule, plants sold in bunches, finely leafed (like Cabomba) and with red tints on the leaves require very bright light to survive and grow.
I have had problems with even getting supposedly “low light” plant varieties like anubias and sword plants to do well with the fluorescent light that comes with a traditional tank light set up. On almost all my tanks — any taller than 13 inches — I have replaced the plastic hood with a glass canopy and added extra light fixtures, usually two to three times the original number.
All of the fluorescent tubes that came with the lights have been replaced with special plant lights. When money is not a hindrance, I have had a lot of luck with Spectrum 5 and Trilux tubes sold at aquarium stores. These cost about $10 – $20 apiece.
A cheaper alternative that works almost as well can be picked up at a hardware store. GE brand Grolux fluorescent tubes are available in 24 inch and 48 inch lengths and seem to work well for aquariums.
These are bout $5 – $10 apiece. In addition, light output can be increased by using the shiny side of aluminum foil as a reflector behind the bulb.
For larger tanks (four feet or more), shop lights that hold two to four bulbs can be used in conjunction with glass canopies to provide a less expensive, though somewhat less aesthetically pleasing, light source. I have purchased very basic ones for about $10.
Additional lights can also be added by using 24 inch fluorescent strip lights available at hardware stores.
Since I really like the look of heavily planted tanks, my rule is the more light the better. All of my lights are on timers; most are on 14-16 hours per day. Additionally all the electrical gadgets for my tanks are plugged into a strip outlet with a circuit breaker.
It is probably correct to assume that most plant failures have to do with lighting, either simply not enough light or attempting to raise plants that are not receiving the correct spectrum of light.
It is very hard to have to much light, and most tank covers with a single light strip will not provide the amount of light needed for healthy plant growth, except for some of the plants with low light requirements.
Unfortunately, most of the plants that require low light also tend to be slow growing and will not compete well with algae.
Most ‘plant-people’ suggest a minimum of 2 watts of light per gallon with 3-5 being needed for best results. Another rule of thumb is, the deeper the tank, the more light needed. Put simply, as light travels thru water it’s intensity weakens.
The source lights color spectrum is of importance to the plant keepers success and I hope to add a page devoted to light color spectrums and the various bulbs that are available to the hobbyist. For now if you are seeking further info on that I would recommend reading the Aquaria FAQ’s on plants that are reachable from our Aquatic Links page.
There are many products on the market that are of aid in keeping plants in the form of fertilizers and substrate preparations. These are inexpensive and available at most Aquatic retailers.
Adding Carbon Dioxide
A more elaborate approach, be it more expensive, is the addition of supplemental carbon dioxide. However, this is an area that you should approach with caution and study beforehand.
There is little doubt that carbon dioxide will benefit your plants but it is also true that it can cause wide Ph swings (remember fish stress?) and careful monitoring will be necessary.
It must be remembered that carbon dioxide and lighting have a very direct correlation on Ph and monitoring should be done both when lights are on and when they are off.
With lights on, plants take in carbon dioxide and when lights are in the dark they release carbon dioxide, thus creating differences in ph with each cycle.
The last thing that seems to have a big impact on the health of the plants is regular supplements with a good plant fertilizer rich in iron. This seems especially true for Vallisneria and some sword plants.
Without the supplement these aquarium plants tend to yellow and grow fewer leaves. I have recently set up a tank using laterite, an iron-rich clay, in the substrate. I’ll let you know how it works.
A number of people have expressed to me their desire to grow flourishing plants without the special lights and without special fertilizers. All I can say is that it didn’t work for me.
When making the special efforts for my aquarium plants, I remind myself that if these were house plants or garden plants, I wouldn’t expect them to grow with poor light or soil conditions. So in some ways, aquarium plants are easy — at least I don’t have to remember to water them.