Live Plants in a freshwater aquarium are a great addition to most tanks. Unfortunately, there is a lot of information out there and it can be tough to figure out what all you really need to do to successfully grow live plants.
I have always kept pretty basic, low-tech planted tanks. I have never gotten in to CO2 gas, super intense lights, soil substrates, etc. This article will take you right up to the point of taking that step into going high-tech, but if you and your tank truly grow to that point, you will probably need some more advanced resources than this one article.
The most important thing to understand with live plants is that everything needs to be kept in balance. Lighting, nutrients, temperature, and CO2 all need to be kept in balance. It will never be perfect, but doing more of one because another is lacking will only keep things more out of balance. You will always have a limiting factor in the tank. As you and the tank progress, the limiting factor will change. There’s no point in adding fertilizers or CO2 if the light is too weak.
When you first start with live plants, your limiting factor will almost certainly be lighting. Most standard light fixtures will have nothing more than one standard output bulb or basic LEDs. This might be enough for the least demanding plants, but even then they won’t usually do that well and most likely you and your tank will outgrow the basic lights very quickly. Upgrading to something along the lines of an adjustable LED fixture is ideal. For a complete explanation of all things lighting, please read the Guide to Lighting an Aquarium.
Quick Summary: On smaller tanks, something like the Nicrew LED is great. On larger tanks, I go straight to black box LEDs made for reef tanks. You can adjust the color and intensity to get exactly what you want.
As you increase your light, the balance will need more nutrients. I would start with two things: root tabs and a general liquid fertilizer. I like Seachem Flourish Root Tabs. Just follow the directions, they will turn any substrate into one with the nutrients needed for root feeders such as swords. This will work with inert substrates such as the Estes Marine Sand (aka Stoney River and Ultra Reef) that I recommend for almost any tank.
As for the general liquid fertilizer, I prefer either Seachem Flourish Comprehensive Supplement or AquaVitro Envy. AquaVitro is a top-shelf brand made by Seachem that is not available online (the company will not sell to anyone who tries to sell it online). AquaVitro products are very good and definitely a great, high-end option for planted as well as reef tank supplements. At this point, the general additive should be all that you need.
Start with less of the general fertilizer than you think you need, the system isn’t used to the extra nutrients, so you need to give it time to adjust. This means you may just be adding 1/4-1/2 dose each week. This is best done after a water change so that you don’t remove it with a water change and it’s there all week for the plants to use.
Don’t just add supplements if you don’t see a difference. If you start to add fertilizer twice weekly instead of once and after a month you see no improvement, then step back down to once weekly, that is not your limiting factor.
At this point, the tank’s limiting factor may be one of a few things. It may be iron, CO2, light, etc. It may be appropriate to break my usual rule of only testing nitrate. Now you can start looking at the things known to limit plant growth: nitrate, phosphate, iron, GH, KH, and CO2. In most tanks, there will be enough nitrate and phosphate, but they are worth checking. If the tests show something is inadequate then buy a supplement for that specific chemical and dose as needed. Never dose something without testing for it and knowing you actually need to dose it. Start with half of what you need, it is easier to add more than to take any out. Again, the system isn’t used to the extra nutrients and the plants need to adjust to start taking advantage of it. Test frequently when you start dosing something new. Once you get it figured out you can back off the testing a little and just test periodically to see if the tank’s needs have changed.
I’ve never used a special plant substrate. I’ve never had CO2 and super intense lighting to need it. I use Estes Marine Sand (aka Stoney River and Ultra Reef) and have never had problems keeping plants happy with it. They all do well to too well. Iron-based plant substrates can get stuck on magnetic algae scrapers and scratch the glass. Specialized dirt substrates just sounds way too messy to me. I can’t imagine just dumping soil into an aquarium. I know it works well for many people, but it’s the last thing I want to mess with.
I just want people to know that you can have a heavily plants tank with plants that are truly thriving with an inert substrate.
I personally do not like to use CO2 gas. Even the best regulator systems can fail on and release too much CO2. This can cause a pH crash and kill everything in the tank. My tanks are fish tanks first, plant tanks second. To me, this means I will not do something to benefit the plants that is a risk to the fish. If you choose to add CO2 gas, make sure you have a good system, step up the use slowly, use as many redundant systems as possible, and only do what is needed to make the difference for the balance of the tank.
Seachem Flourish Excel is a liquid carbon source. When I tried it, I had some cabomba grow approximately 4″ in 24 hours. Obviously, carbon was the limiting factor in my tank at that time. As always, start with less than you need. Be aware though, Excel is not just another fertilizer, it can be toxic (to you and other life) so do some research before jumping into using it. There are certain plants, inverts, etc. that it should never be used with at all.
Carbon Filter Media
Be aware that carbon will remove chemicals, including your fertilizers. Any tank should be well-maintained enough to not need carbon, so you should be able to simply stop using it completely. The main things it removes are odor and discoloration, both of which are kept under control with adequate water changes. Big weekly water changes will remove all the bad stuff that carbon does. This is why I insist on big weekly water changes, even if the nitrate is fine, the fish seem fine, etc.
Most people will say that the ideal filter for a planted tank is a canister since it will have minimal surface agitation which can drive off CO2. Again, my tanks are fish tanks first so I stick with HOBs and even use air stones. If you decide to go beyond what I do with my tanks, then yes, a canister will be ideal. Any filter needs to be well maintained, at least once per month. Even if the tests show everything is good, in order to keep it that way, you need to stay on top of the maintenance. For more information, read the article on Filter Types.
At the end of the day, almost all tanks need some algae control, and planted tanks are even more likely to since you are promoting photosynthetic life. Keeping things in balance will help immensely. In addition to this though, you may need to hire some 24/7 labor to keep the algae in check. My top picks are bristlenose plecoes since they will not bother plants but will eat almost any type of algae. In very small tanks and when brown algae is the problem, otocinclus are a great option. (Brown algae is usually eliminated by replacing the light bulbs and/or getting a more intense light fixture since brown algae is a low-light algae.) If black hair algae is the problem, then get some Siamese algae eaters. Flying foxes are commonly sold as Siamese algae eaters, but you can identify the Siamese algae eaters since they have a zig-zag edge to their black line and the black line extends into the tail. Don’t simply add fish as your way of controlling algae. They can certainly be part of the solution, but figuring out what is out of balance is a vital part of the solution. If you’re not doing large enough or frequent enough water changes, your lights are on too long, etc., then you may have bigger issues to correct before adding algae eaters.
Water changes are something that many planted tank keepers begin to slack on because the live plants can help water quality, particularly nitrate. It is possible for well-balanced planted tanks (lots of plants and a low bioload of fish) to have little to no nitrate. However, since nitrate is not the only bad thing that builds up and lowers water quality, you still need to maintain a good weekly water change schedule. Even if the tests show everything is fine, you need to do weekly water changes of at least 25% bare minimum. This will help guarantee that the water quality never becomes a problem. For more information on water changes and water quality, read the article on Water Changes and Water Quality.
I tried all sorts of plants over the years. I did not follow the usual rules of sticking with low-light, medium-light plants, etc. I just tried what I liked and it went very well 95% of the time. I am sure many of them would have done even better under perfect conditions, but I am not worried about perfect. If a plant lives but doesn’t grow as quickly, isn’t as full, etc. I am okay with that.
It isn’t a bad idea when you are first starting to stick with some low-light plants so they will have the best chance of settling in well and thriving. Then, once you get the basics figured out, you can start trying different plants that you like and worry less about their perfect lighting preferences.
Low Light Plants/Good First Plants:
- Crypts (can grow well on driftwood, not just in the substrate)
- Vals such as jungle val
- Tiger Lotus, both red and green (I love these plants)
- Many stem plants such as Cabomba, Anacharis, etc. will do well unless you have a tall tank, relatively weak lights, and the light doesn’t get down to them.
I didn’t list Java fern or Anubias because although they are low-light, they are pretty slow-growers even if everything’s right for them, so it can be hard to tell the difference between them doing well or just good enough to not die. Feel free to try them if you like them, but they’re not the best indicator that things are good for other plants.
Avoid java moss, it can get out of control. At first, you won’t mind, you will just be happy something is living and doing pretty well. But as it gets out of control, it can be tough to get rid of. It can get to the point of clogging filters, it isn’t fun. Don’t mess with it. Be aware that some moss balls are just balls of java moss, not true moss balls. I have seen this at Petco and Petsmart, so beware.
There are lots of lists and guides online, I encourage you to check them out just to get an idea of the order of plants you should try before others, just don’t avoid medium or even high-light plants until you try them, you never know how well they will do for you.
With live plants comes the very real (and likely) risk of introducing pest snails to the tank. If you have a planted tank you will almost certainly bring in snails sooner or later. Even if you carefully inspect every leaf of every plant you buy before you add it to your tank, you can easily miss a whole cluster of eggs. Some people go as far as bleaching their plants or dipping them in various prophylactic treatments such as alum or potassium permanganate. I have never done this, it seems a bit overkill to me. The few pest snails I have seen over the years I removed manually or I added loaches which kept them under control for me.
Nerite snails are becoming quite popular and are a great, plant-safe snail to help with algae in a planted tank. They stay relatively small and come in a wide variety of patterns (mostly green or brown base with black markings). In addition, they need brackish water to reproduce, so they will not take over a freshwater tank.
Malaysian trumpet snails are great at helping to keep the substrate aerated and clean. I haven’t found them to be necessary with the Estes sand I recommend, but it certainly won’t hurt to have them (especially if you don’t have fish that dig through the substrate such as goldfish or cichlids). Some people don’t like them because their population can get out of control, but I haven’t found this to be true in clean tanks that are not overfed.
Controlling snails once they are already in can be a bit of a headache. The simplest solution is manual removal, but if there are too many or they just never seem to stop showing up, then more aggressive actions need to be taken. Be aware that if you also have snails that you want to keep, then manual removal is generally your only option. Loaches are great at eating snails, they love them. Assassin snails are another option, if you can find them. I generally like fish, including loaches, so I usually just add a trio of a nice looking loach that is an appropriate size for the tank (some loaches get too large or rambunctious). Be aware that clown loaches have been known to eat holes in plants (they also get huge, so they should be avoided in most tanks anyway).
Fish and Plants
Although there are lots of fish you can keep with plants, there are some limitations you should be aware of.
Silver Dollars – The worst fish to put with plants are probably silver dollars. They are so herbivorous and love plants so much, I don’t think I’ve ever seen someone keep them in a planted tank (if you have or know of an exception, please email me!). I’ve wanted to try, and if it worked, it would require a large tank with tons of plants that are well-established before the silver dollars are added. Even then, I wouldn’t be surprised if the silver dollars proved to be too much over time.
Community Fish – Almost all community fish are perfect with plants. Even highly herbivorous species such as mollies are too small to actually chow down on most plants, but they will graze on the algae for you.
Algae Eaters – Most algae eaters such as plecoes and Siamese algae eaters eat algae, not plants, so they’re safe with plants. There are lots of species of plecoes though, so not all are safe with plants (common plecoes would be a huge no).
Cichlids – Most smaller New World cichlids such as rams are great with plants. However, large fish that constantly rearrange their tank such as Oscars would at least uproot them if not enjoy tearing them apart even if they don’t eat them. Herbivorous cichlids such as the mbunas from Lake Malawi will usually uproot and/or eat the plants, but some people have had success with fast-growing plants such as jungle vals. Just don’t hold your breath when pushing the limits.
Goldfish – Goldfish are known to eat plants, but I’ve found this is 80% wrong. Fancy goldfish will nibble plants, but in my experience, as long as you add a lot of plants at once (ideally when the goldfish are still small), the plants can outgrow the nibbling. It doesn’t work if you try a few plants to see how they’ll do because the goldfish will overwhelm the plants. Adding a lot at once spreads out the nibbling so that all the plants can grow faster than the goldfish will eat them. In addition, plants LOVE goldfish water, so they tend to grow pretty well in fancy goldfish tanks if the light is adequate.
Don’t be intimidated by plants. They’re easier than most people make them out to be and the usual problems are pretty simple to address (such as lighting). They add an amazing new dimension to a freshwater tank.