How to Care for Compacta Plants in an Aquarium

-- By Carol

It’s hard to go wrong with Compacta plants in your aquarium. They grow well without strong light.

They don’t require an unusual pH that interferes with fish care. They respond to fertilizer, but they don’t require it.

The only thing that you will have to do to care for your Compacta plants is to make sure they don’t do so well that they take over your aquarium.

Fortunately, compared to the other aquatic plants to which Compactas are related, they stay relatively small.

In this article we’ll tell you everything you need to know about taking care of Compacta plants in your fish tank, starting with what exactly a Compacta plant is.

Table of Contents

What Is a Compacta Plant?

The Compacta plant is actually a miniature strain of an Asian water plant known as hygrophila, or by common names like Temple Plant or Starhorn, or by its scientific name Hygrophila corymbosa.

When you are shopping for the smaller Compacta plants, you will want to avoid the variety of Hygrophila corymbosa known as Giant Hygro.

Compacta is a member of the acanthus family, a group of over 3,000 plants including many popular house and garden plants.

It was developed from Giant Hygro, which is abundant in Southeast Asia. It has escaped aquariums and become an invasive plant in Florida.

In nature, Hygrophila is a flowering plant that grows in water, but not necessarily underwater.

It is only very tolerant of flooding. It doesn’t actually prefer to live underwater. It will naturally try to grow to reach the surface of the water in which it is growing.

If you let your Compacta plants grow out of the tank, it will drop its underwater leaves and put on purple flowers.

For this reason, it is a good choice for a paludarium (a combination of an aquarium and a terrarium), but it will need to be placed in the background so its bare stems don’t distract from the underwater scenery.

In Thailand and Malaysia, Compacta and its close relative Giant Hygro are used in herbal medicine for treating fevers. They also have been studied as part of a treatment for malaria.

Compacta is a great plant for people who are just setting up their first aquarium.

There are conditions in which it will grow better than in others, but it survives even serious plant-keeping mistakes.

If you keep Compacta, however, you need to understand upfront that you will need to trim it regularly to keep it from taking over your aquarium.

Buying Compacta Plants

You should be able to find Compacta plants in an aquarium supply store for just $5 to $10. (In this article, all prices are in US dollars.)

When you are buying Compacta plants, you want to avoid Giant Hygro plants, which are suitable only for the largest aquariums (more than 55 gallons/200 liters).

It is important to buy only plants with vibrant green colors.

Faded colors are caused by lack of light, growing the plant in water without any nutrients at all (just in water, without fish, and without fertilizer), or by exposure to extreme cold or extreme heat.

Compacta plants with faded leaves will probably never grow even after you transplant them into a well-prepared aquarium.

Using Compacta in Your Aquarium Design

Compacta is an elegant plant. It doesn’t have frilly leaves or unusual colors. It simply stands tall as a background plant.

Compacta plants have broad leaves. The width of the leaves intensifies their bright green color.

The stems of the Compact plant are thick and more intensely colored than the leaves, often a dark bronze.

But your Compacta plant will fade out if it doesn’t get enough light and nutrients.

Under ideal conditions, a Compacta can grow to a height of about 24 inches.

You should not put it in a tank that is less than 24 inches deep, or it will focus its energy on growing above the surface.

The leaves of your Compacta plant can extend about 3 inches away from the stem.

You can manage your Compacta plant’s habit, however, by keeping its leaves trimmed.

Setting Up the Tank for Compactas

In nature, Hygrops grows in marshes with silt or sand beneath the water. Even if you can find silt, you don’t want to put it in your aquarium.

When you are growing Compactas, you want to use sand as the substrate in the bottom of the tank, at least in the back of the tank, where you are putting your Compactas.

Because Compactas need to be anchored in sand, this means that they are not good tank mates with plants that need to be anchored in grit or gravel.

Compactas don’t grow well alongside Amazon Swords, Anubias, Bucephalandras, Java Ferns, Madagascar Lace, Red Tiger Lotus, or Vallisnerias.

Sandy substrate also affects which fish you can keep. Cichlids need sand to help them digest their food.

They are very compatible with Compactas. Goldfish, on the other hand, risk intestinal blockage if they swallow sand.

They need a gravel substrate, so they aren’t compatible with Compactas in the same aquarium.

Growing Conditions for Compactas

Compactas grow best at temperatures between 72° and 84° F (22° and 28° C). They are OK in moderately acidic to mildly alkaline water, with a pH of 6.0 to 7.5.

It thrives in water hardness of 3 to 18 dGH, or up to about 360 parts per million.

Compactas grow better in intense light, but you don’t actually want your Compactas to put on heavy growth. That creates more work to keep them trimmed.

As long as there aren’t any floating plants between your Compacta and their light source, they should be fine.

Compactas that don’t get enough light will become leggy and spindly as they try to reach the surface.

Providing CO₂ and a fertilizer that contains iron and potassium will help if your Compacta start to wilt.

Ordinarily, Compacta get all the fertilizer they need from fish waste.

Just be sure you place your Compactas in a tank that holds at least 20 gallons (80 liters) to fully appreciate their height and strength.

Taking Care of Compactas

There isn’t a lot you need to do to take care of Compactas on a day-to-day basis.

About once a week, it helps to wipe away any algae that blocks light.

Although Compactas help maintain good water quality by using the nitrites released by fish waste, partial water changes every week, no more than 5 gallons at a time, keep the nitrites, pH, and hardness within healthy limits.

A phenomenon you will want to avoid is called “melting.” Sudden changes in water conditions, whether its temperature, pH, nitrites, or hardness, can shock your plants.

If this happens, avoid making other sudden changes to the water unless it has become extremely polluted by waste, and trim back the plant to give it a chance to grow healthy leaves again.

Trim Compactas that are growing out of the water or crowding other plants in your tank.

Don’t let them obscure your view of your fish. Encourage healthy leaf growth up and down the plant by cutting back leaves that block light to the lower part of the plant.

Propagating Compactas

You don’t always have to spend another $5 or $10 when you want to add Compactas to another aquarium. Compactas are easy to propagate for new plant.

The first step in propagating Compactas is preparing the substrate for the new plant.

Compactas don’t have to have fertilizer in their substrate, but a substrate that contains fertilizer or adding fertilizer to the sandy substrate will set up your cloned Compacta for healthy, fast growth.

The next step is cutting off a side shoot of the Compacta plant you already have in your aquarium.

Choose a side shoot that already has leaves. Place it in a well-lighted location in the background of your aquarium and simply wait for it to root and start to grow.

You can also root cuttings from the top of your Compacta plant. Make sure they have a few leaves before you place them in the substrate.

Frequently Asked Questions About Growing Compactas

Q. Are Compactas suitable for outdoor growing?

A. Compactas survive in warm-winter climates like South Florida and the Rio Grande Valley of Texas, although the occasional hard freeze will kill them off.

But they are not suitable for outdoor fishponds, because they can become invasive if they escape their pond.

It’s recommended that you kill Compacta cuttings from your aquarium with bleach before you place them in your trash to keep them from taking over nearby lakes, rivers, and streams.

Q. Are there any crustaceans that are compatible with Compacta plants?

A. Ghost shrimp and Mystery Snails will leave Compacta plants alone.

However, freshwater crabs and crayfish will destroy them.

Q. Are there any fish that should never be placed in the same aquarium with Compactas?

A. Oscars almost always will destroy Compacta plants.

They need to be put in a tank decorated with artificial plants.

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