A Simple Guide to Aquarium Fertilizers

Aquarium fertilizers are more essential in high-tech aquascapes since the growth rate of plants in high-tech aquascapes is fast compared to their low-tech counterparts. Low-tech aquascapes generally do not need additional fertilizers since the essential nutrients are supplied by fish waste. In high-tech aquascapes, if carbon dioxide and lighting is sufficient, the only limiting factor to plants’ growth is the lack of essential nutrients. Fish waste alone will not be sufficient to supply the nutritional needs of the fast growing plants of high-tech aquascapes.

Nutrients that are essential for plants are classified as macro nutrients and micro nutrients. Macro nutrients are Nitrogen (N), Phosphorous (P), and Potassium (K). While Nitrogen and Phosphorous are abundant in aquarium water, Potassium is usually scarce. Dosing additional Potassium in aquascapes is recommended to keep the level of macro nutrients on a stable level. The lack of Potassium in the aquarium can be observed from the yellowing of the plants’ leaves. Dosing excess Nitrogen and Phosphorous will definitely lead to algae outbreaks and, therefore, contrary to standard aquascaping advice of adding all macro nutrients into the aquarium, I would advise only to add Potassium as an additional macro nutrient fertilizer.

Micro nutrients, or trace elements, are magnesium, copper, iron, manganese, molybdenum, zinc, cobalt. Some other elements are also classified as micro nutrients but the elements listed above are the most essential elements for healthy plant growth. Aquatic invertebrates, especially shrimps, are extremely sensitive to copper. If you have shrimps in your tank, it is better not to fertilize micro nutrients to the tank since most micro nutrient fertilizer contains copper. If you plan on adding micro nutrients to the tank, add only copper-free fertilizers if you have shrimps in your tank.

Aquarium fertilizers come in many forms. Fertilizers can be classified as one of the following types: substrate fertilizers and liquid fertilizers. Substrate fertilizers are mixed with the base substrate before the aquascape is constructed, therefore, these types of fertilizers are used only once in your aquascape if you do not plan on re-scaping your aquascape in the future. Substrate fertilizers are usually buried beneath an inert substrate material, such as holland sand or other decorative substrates, to prevent nutrients leaching to the water column, which could cause algae outbreaks due to nutrient imbalances. Liquid fertilizers are recommended for aged aquascape since they are easily injected into the water column or to the base substrate by using a syringe.


How to Set Up Pressurized CO2 System

If you are looking to create a high-tech aquascape, it is essential that you add a pressurized CO2 system for your plants to grow properly. Without proper amount of CO2, the bright lights and nutrient-rich substrate of high-tech aquascapes will quickly create a state of imbalance for the aquarium ecosystem, which will cause algae outbreaks. This article will explain how you should setup a pressurized CO2 system for your aquascape.

Before you start installing your CO2 system, you will need to purchase or obtain these essential equipments for the system itself. An in-depth topic of each of the equipments listed below will be on a different post:

  1. Pressurized CO2 tank
  2. CO2 regulator
  3. Check valve (optional)
  4. Bubble counter
  5. CO2 Diffuser
  6. High-pressure hose for CO2
  7. CO2 indicator

After obtaining the equipments listed above, connect the parts using the high-pressure hose in order from item 1 to 5. Note that only item 5, i.e. CO2 diffuser, should be inside of your aquarium water. Other items should stay out of your aquarium water.

Install CO2 indicator in your aquarium and place the item on the opposite end from where you attach your CO2 diffuser to get an accurate reading. The reason for this is obvious: the closer the indicator is to the source of the CO2, the more CO2 the indicator should read. We want the indicator to show whether the CO2 levels in the furthest spot gets enough CO2. Also note that the CO2 indicator should be placed below the halfway mark of your aquarium tank to avoid false reading due to diffusion of CO2 from the water surface.

After completing the steps explained above, your pressurized CO2 system is ready for use.

Rotala Macrandra – Giant Red Rotala

Rotala Macrandra, or the Giant Red Rotala, is a plant native to India. This plant is quite demanding in terms of lighting intensity and nutrient availability. To show this plant’s true potential, CO2 injection is necessary and iron supplements must be applied to the aquarium water. High lighting intensity is also essential to produce healthy plant growth.


Low Nitrate (NO3) levels with high Phosphate (PO4) levels will result in compact, bright red growth. High NO3 levels and low PO4 levels will result in leggy and light orange growth. Iron and micro nutrients supplements are required for optimum and healthy growth.

Rotala Macrandra is often used as an accent plant or focal point due to its beautiful red coloration. This plant can also be used as a background plant. If given enough CO2 and high lighting, this plant will produce oxygen bubbles or a pearling effect.

Rotala Macrandra – Plant Profile:

  • Position: Midground, Background
  • Hardiness: Difficult
  • Lighting Requirement: Very high
  • Plant Structure: Stem
  • Origin: India, South Asia
  • pH: 5.0 – 6.5
  • Temperature: 22 – 28° Celsius
  • Size: 20 – 50 cm tall
  • Growth Rate: Fast
  • Emersed Culture: Yes
  • Price: Moderate

Hemianthus Callitrichoides – Dwarf Baby Tears

Hemianthus Callitrichoides, or commonly called Hemianthus Cuba or Dwarf Baby Tears, originated from East Havana in Cuba. This plant is currently the smallest carpetting plant that is available for aquascaping. Given enough CO2, lights, and nutrients, this plant will grow moderately fast. Increasing CO2 and light intensity will definitely increase the speed of growth.


In aquascapes, Hemianthus Cuba is commonly found in Iwagumi aquascapes or in nanoscapes where a sense of depth and vastness is required. This plant is good for filling in tight spaces in your aquascape. I have found that this plant can also be used to fill in crevices between rocks or driftwoods.

This plant is usually sold in small pots. To plant them, simply separate each stem and plant individually into the substrate. If this method is too time-consuming, we could also plant them in clusters that contain a few plantlets at a time.

Hemianthus Callitrichoides – Plant Profile:

  • Position: Foreground
  • Hardiness: Moderate
  • Lighting Requirement: High
  • Plant Structure: Stem
  • Origin: Cuba/Central America
  • pH: 5.0 – 7.5
  • Temperature: 18 – 28° Celsius
  • Size: 1-2 cm max.
  • Growth Rate: Medium
  • Emersed Culture: Yes
  • Price: Moderate (usually sold in slabs or pots)

Glossostigma Elatinoides – Glosso

Glossostigma Elatinoides originated from Australia and New Zealand, where it grows in bogs and swamps, either partially or fully submerged. This plant is relatively easy to grow, given enough light and nutrients.


Glossostigma Elatinoides is best placed in the foreground as a carpet plant. Some aquascapers also use this plant all over the aquarium in iwagumi-style aquascapes.

The only issue that most aquascapers has with Glosso is how to keep it growing low. Most of the time, increasing light intensity and increasing CO2 are enough to keep Glosso low.

If that method does not work, then we can train Glosso to grow low by snipping the top node of the plant and planting the cutting again into the substrate. Repeat this process until the plant grows horizontally. After a while, if this method does not work as well, you will need to check the light intensity and CO2 levels in your aquarium.

Glossostigma Elatinoides – Plant Profile:

  • Position: Foreground
  • Hardiness: Moderate to Difficult
  • Lighting Requirement: High
  • Plant Structure: Stem
  • Origin: Australia and New Zealand
  • pH: 5.0 – 7.0
  • Temperature: 22 – 36° Celsius
  • Size: 5 cm
  • Growth Rate: Very fast
  • Emersed Culture: Yes
  • Price: Moderate

Hyphessobrycon Sweglesi – Red Phantom Tetra

Hyphessobrycon Sweglesi, used to be called ‘Megalamphodus Sweglesi’, is a stunning aquarium fish that originates from Orinoco River drainage basin in South America. This fish, which is commonly called as the ‘red phantom tetra’, has a beautiful deep-red colouration, with a black spot behind its gills on both sides of its body.

Being a full-bodied tetra species, Hyphessobrycon Sweglesi is best kept in jungle-style aquascapes in large schools. Red phantom tetras are similar in appearance to Serpae tetras or scientifically known as Hyphessobrycon Eques, but red phantom tetras exhibit a rounder black spot behind their gills.



This fish originated from South America, particularly Orinoco River basin.


Blackwater, tannin-stained biotope in sluggish river tributaries, which is highly acidic.

Maximum Size

Red phantom tetras reach a maximum size of 4 cm. The minimum tank size for these fishes is 60 cm tank.

Water Conditions

Water condition should be slightly acidic with a pH of 5.5 – 7.0 for optimal living conditions. The gH or hardness should be kept between 1 – 12. Best temperature for this species is 22 – 28 degrees Celsius. This fish tend not to show optimal colouration and behaviour in alkaline waters.


This species is a good community fish, i.e. they can live well with other peaceful species. Red phantom tetras are better choices of fish other than the Serpae tetra, which is usually more active. It is best to keep 6 or more of their own kind to avoid any feeding and behaviour abnormalities.

Hyphessobrycon Eques – Serpae Tetra

Hyphessobrycon Eques, or Serpae Tetra, is a full-bodied tetra that originated from the Amazon River and upper Paraguay. This fish is similar to the Red Phantom Tetra, but they do not possess the deep red dorsal fin. Their temperament is also more aggressive than the Red Phantom Tetra. In aquascapes, these tetras are commonly used in jungle style aquascapes due to their attractive colours.

Serpae tetra


This fish originated from the Amazon River and upper Paraguay.


Amazon Basin, with many South American aquatic plants such as Myriophyllum and Echinodorus.

Maximum Size

Serpae Tetras reach a maximum size of 5 cm. The minimum tank size for these fishes is 60 cm tank as they are tight schooling fishes.

Water Conditions

Water condition should be slightly acidic with a pH of 5.0 – 7.8 for optimal living conditions. The gH or hardness should be kept between 0 – 15. Best temperature for this species is 24 – 27 degrees Celsius. To breed, the water needs to be 28 degrees Celsius.


This species is a good community fish, i.e. they can live well with other peaceful species. Since Serpae Tetras form tight schools with their own kind, keep 6 or more of the same species to observe their normal behaviour. Serpae Tetra may be aggressive towards other mild tempered fishes.