Singapore Web DesignerA Guide to Glossostigma elatinoides » AEN—Designer & Consultant

First published in 2004 in my old AQUOI Blog.

Introduction

When I first started seriously making Nature Aquariums, I was introduced to Glossostigma elatinoides by a staff at Sam Yick’s Aquarium at Pet Safari Singapore. I was a newbie and I just wanted a foreground plant, not knowing how the art of growing Glossostigma elatinoides is so hard to grasp. As with most amateurs, my first experience was a painful and long one. But I have come a long way and somehow managed to successfully grow it and developed a deep love for it. Now my favorite plant, I want to share my knowledge of it with everyone. Thus, I have written this article as a more comprehensive, down to earth and informative guide to those interested in the plant that was introduced to the aquascaping world by Takashi Amano in the late 80s.

Summary

I will discuss the history of the plant, how it came to the aquascaping world. The biological profile of the plant will also be discussed. I will also touch on the various methods of cultivation, propagation and pruning techniques. Lighting levels, fertilization and CO2 levels which are equally important, will also be discussed in detail.

It will be a long and dedicated article on my favorite plant created based on my personal experience, online research, accounts of other hobbyists and scientific materials.

Profile of Glossostigma elatinoides
(Information from Tropica.com)

Family:	Scrophulariaceae
Continent:	Australia
Country of origin:	New Zealand
Height:	2-3+cm
Width:	3+cm
Light requirements:	high - very high
Temperature:	15 - 26 °C
Hardness tolerance:	very soft - medium
pH tolerance:	5 - 7.5
Growth:	fast
Demands:	very difficult

Quoted from Tropica:
Glossostigma elatinoides is much in demand in Japanese-inspired aquariums. It is one of the smallest aquarium plants, and thus a good foreground plant. A difficult plant demanding a lot of light. Grows upwards if light is poor. Make sure larger plants do not overshadow it. When planting in the aquarium small clumps (approx. 1/8 pot) should be placed at intervals of a few centimeters to help the plants grow together more quickly. CO₂ addition and soft water promote growth significantly.

History of Glossostigma elatinoides in the Nature Aquarium
(Based on information from Suiso.com)

Glossostigma elatinoides was brought into Japan in the late 80s. Nature Aquariums was not new at the time but there were not many choices for foreground plants except Echinoderus tenellus.

While looking for low growing plants in overseas magazines and plant books, Takashi Amano came across some Glossostigma elatinoides in European Style Aquarium Magazine. It was not the first time Mr Amano had seen pictures of Glossostigma elatinoides, those he have seen were always growing vertically due to low lighting. Those in the magazine were however, different. They were growing horizontally. Mr Amano then contacted Dennerle Co. of Germany. He found that Glossostigma elatinoides was not very popular in Europe and Dennerle was out of stock. Eventually Mr Amano got one box full after much persuasion.

After the plants left Europe, ADA ran into problems with the customs who had no idea what the plant was, what Family it belonged to as no one had tried to import this plant into Japan before. The customs called ADA but Mr Amano was out of town and the staff of the ADA headquarters had to answer all the questions. Unfortunately, the plants still had to stay overnight. To make matters worse, it was in the middle of summer.

Mr Amano returned the next day. Upon opening his treasure box, Mr Amano said, "Ahhhh"! Most of the plants had turned brown and was melting and only a few green leaves were left, mostly index finger size. Mr Amano put all the green leaves into a 60cm tank and gave them lots of light and CO₂. For several weeks it did not grow. The ADA staff gave up and didn’t care for that aquarium anymore. Only Mr Amano himself cared for it.

Mr Amano set up the most favorable condition for the plant in the aquarium, which included adequate light, CO₂, Iron and Potassium. After a few months it started to put out runners and grew fast after that, eventually covering the 60cm aquarium. By using the same Glossostigma elatinoides Mr Amano created the first Glossostigma elatinoides Nature Aquarium layout for another 60cm tank and a 90cm one.

After publishing the pictures of the aquariums above in a Japanese aquarium magazine, ADA received lots of orders for Glossostigma elatinoides. Back then it cost about 2000Yen ($18US) for a sprig of Glossostigma elatinoides.

Lighting

If we were to use the traditional watts per gallon rule to describe the lighting needed by Glossostigma elatinoides, one would need more than 3 W/g in a typical 60×30x36cm tank. On my main 60cm Glossostigma tank, I am using 2×36W compact fluorescent tubes which yields about 4 W/g, which is considered by many to be a "high light" tank. But lighting is actually more complex than wattage over volume.

A good way to know what Glossostigma needs is to look at other successful Glossostigma tanks. I had done extensive research on Takashi Amano’s lighting patterns used in Glossostigma tanks and found that the watts per gallon rule does not seem to apply. In Mr Amano’s tanks, smaller tanks usually have higher lighting than big tanks. A detailed article on this can be found in this article on Fitch family’s web site. Usually, the W/g rule works and using 3-4W/g will help Glossostigma put out horizontal runners.

Other than the wattage of lights, a good lumens output is essential for a lamp used for cultivating aquatic plants. Lumens refer to
Unit of measure for amount of light produced by a lamp once it is started. One lumen equals one foot candle per square foot. High light intensity provides more energy to the plants for photosynthesis.

The "K" rating is also very much discussed in Aquarium discussion boards. It is known as the Color Temperature and refers to
Temperature of the black body that emits radiation of the same chromaticity as the radiation considered.
Unit Kelvin, K. Many people like to use 5400 - 6500K rated lamps as it is closest to the color temperature of a midday sun, and that is considered by many to be the best for plant growth. My observation with lamps at such K ratings tend to have low CRI (Color Rendering Index) and appears warm (yellowish/orangish). Takashi Amano uses 8000K lamps which ADA claims to be closer to the exact and perfect temperature plants need. I myself use 8600K Sigma compact fluorescent tubes and I do feel it is not as good as Osram or Philips. The lumens output of my current tubes is also unknown but I had good success with them. Maybe if I switch to a 8000K tube with at least 2900 lumens, I would have better results.

I did not get good horizontal growth when I was using 4×15W FL tubes compared to the 2×36W compact fluorescent tubes now. I also noticed denser and faster growth where it’s brighter under the middle of the tubes.

As with most green plants where chlorophyll is the dominant photoreceptor in the chloroplast, light rich in the red and blue-violet spectrum is favorable. One fine example of this kind of tube is NEC Biolux fluorescent. It appears pinkish but when used with plants, the plants absorb most of the red and blue-violet and reflect the rest of the green off, resulting in natural colors.

Ugly vertical growth due to insufficient lighting

Substrate

A suitable substrate is the next most important factor in the success of growing Glossostigma. Glossostigma roots fast given a fine enough substrate. Make sure the substrate have no sharp edges, as they can hurt the really fine roots. The roots of Glossostigma can go really deep into where it’s fertile and rich. They usually do much better in an acidic and soft substrate where base fertilizer is present. I recommend ADA Aqua Soil used on top of Power Sand. Power Sand is a very rich pumice based sand and can provide the roots of Glossostigma the essential nutrients. Aqua Soil, which is permeable and soft lets mulm settle into the substrate and as they mulm decompose, the nutrients are locked into Power Sand. This means a long-lasting substrate. If the cost of ADA products set you back, consider laterite based substrate and base fertilizers. They should work just fine.

Healthy runners in a good substrate

Fertilization

I will start with substrate fertilization. Glossostigma prefers a rich substrate. I am not too sure what elements are more critical but I feel it is safe to fertilize the substrate with a decent base fertilizer that is rich in all the macro and micro nutrients especially Fe (Iron). As the nutrients do not seep into the water column, algae problems can be avoided and the Glossostigma will have a rich source of nutrients.

Liquid fertilization is more complicated. From my experience, Glossostigma is a heavy user of K (Potassium) and Fe. When deficient, it develops yellowed new shoots and sometimes older leaves stop growing and get taken over by algae. N (Nitrogen) and P (Phosphorous) must be maintained at good levels. Unbalanced and incorrect levels can indirectly Glossostigma as the leaves can be attacked by various algae such as Black Beard Algae and Green Hair Algae. Other essential nutrients include Mg (Magnesium) which is a central component of chlorophyll.

Glossostigma infected with algae due to nutrient imbalances in the water and lack of CO₂

Carbon dioxide

Glossostigma must be grown with pressurized systems. High CO₂ levels must be maintained to ensure healthy growth and algae inhibition. When dealing with high concentrations of CO₂, pH swings become a concern, especially when you have livestock in the aquarium. The DIY system will fail in this case. CO₂ levels of 25-50ppm is ideal. While 20-30ppm is what people do to avoid harming the livestock, I have never observed abnormal behavior or casualties in my tetras and Yamato shrimps at levels of around 47ppm for weeks. High CO₂ promotes higher photosynthesis levels which enrich the water with oxygen which will benefit all living organisms in the aquarium.

High CO₂ is especially important when you have intense lighting. Failure to provide high levels of CO₂ to Glossostigma under intense light will result in slow growth. Algae will will then infect the leaves. The red algae infected leaves appear darkened at the leaf blade edges and subsequent darkening of the whole leaf. Hair algae infected leaves will appear fuzzy or furry. Green spot algae can also occur on the leaves under high light and low CO₂. Weak and unhealthy leaves worsen the problems.

Algae infected leaf edges

With high light and high CO₂, Glossostigma leaves start to bubble and pearl, a truly pretty sight to behold. However, there is also a possibility of too much CO₂. When leaves are thin and slender instead of tongue-shaped, it is usually a result of over-injection of CO₂.

Planting Glossostigma

Planting Glossostigma is pretty simple. All you need is a pair of sharp scissors and pointed tweezers.

The pic on the left shows some quality tweezers. It is important that the end of the tweezers meet perfectly and are pointed/sharp. This allows the stem of Glossostigma to be inserted easily into the substrate during planting. Thin tips also helps in the minimal disturbance of surrounding substrate. Conventional plant tweezers are not very effective for planting Glossostigma because Glossostigma is small. These tweezers usually have broader tips and will disturb the surrounding substrate.

Glossostigma usually come in rock wool pots when bought from the LFS. They also come attached to driftwood or as a floating clump. Whatever form it comes in, the most important thing is to remove all that is not part of the plant, i.e. rockwool, pots, wood, etc… Then carefully separate the plant into individual plantlets using a pair of sharp and fine scissors.

Individual plantlets

The plantlets are inserted into the substrate until only the top leaves are visible with the stem and roots firmly in the ground. Each plantlet should be planted at intervals around 1-2cm. If you have a lot, plant them closer as it will accelerate the carpeting effect. Once they root, new buds will appear and you should see healthy growth. Glossostigma is a very fast grower and will run over plants in it’s tracks. Take that into consideration when planning your aquascape.

Planting with tweezers

Pruning & propagation

Glossostigma is an epiphytic plant that propagates by runners and respond well to regular pruning. Under strong light and CO₂, Glossostigma quickly forms a thick carpet. Sometimes so thick that the bottom leaves suffocate due to improper water flow and lack of fresh oxygenated water rich in nutrients. Without pruning, the bottoms leaves will rot away and be infested with algae where shrimps and algae-eating fish cannot reach. It becomes very unattractive. Therefore regular pruning is required for the health of the leaves such that the bottoms leaves can stay alive. Regular pruning of the top stems, also known as apical buds which are chemically dominant over the lower shoots will encourage new lower shoots to grow.

Healthy and dense growth often occur when runners pile up on top of other leaves forming thick layers. The upper runners may grow upwards in an disordered fashion. Thinning of the overlapping layers should be carried out periodically to improve circulation and prevent algae growth. To maintain Glossostigma in a low-lying position, the lower leaves which had withered and turned yellow should be pruned away. If leaves are heavily infested with algae or had become moldy, remove the plant and fill the empty patch with fresh and healthy specimens.

Glossostigma can also be "trained" to crawl. When Glossostigma starts to put out a second stem above the first 2 leaves. Trim it near the top of the bottom leaves so you get a plantlet. Replant this plantlet into the substrate and it will root. Another situation is that the stem of Glossostigma starts to grow taller with longer leaf stalks. In this case, plunge the stem further into the substrate with tweezers.

Incredible growth power of Glossostigma elatinoides

Glossostigma elatinoides will flower when grown emersed. For a photo of a Glossostigma flower, click here.

Algae infection on Glossostigma

Almost every type of algae can grow on the leaf blades and stems of Glossostigma. I have had almost every algae on mine, Green Spot Algae occurs under high light intensity and low CO₂ levels. This is due to the poor growth of the leaves when deficient of CO₂. Black Brush Algae also will appear on leaves starting from the edges of blades. A high CO₂ level and a proper amount and balance of Phosphates and Nitrates in the water will inhibit this algae. I have had good growth and BBA at the same time so this algae is probably not associated with poor growth but nutrient imbalances. However, weak and dying leaves as a result of poor growth are hotbeds for algae growth and should be trimmed away. Green Hair Algae occurs at excessive Nitrate levels when plants are not sufficient to absorb them. A combination of pruning and proper nutrient management will eradicate it. Yamato numa ebi is also very effective for this algae. Staghorn algae can also occur but my experience with it is limited. So I cannot comment on its combat strategy. I never had Cyanobacteria at all, I cannot give any comments on this either.

Poor health due to nutrient deficiencies

The most common ailments that can happen to Glossostigma are:
(from Chuck’s Planted Aquarium Pages)

Symptom	Leaves showing symptoms	Deficient element	Common sources
Yellowish leaves, melting	Old	Nitrogen	· Potassium nitrate · Ammonia/Ammonium · Nitrites from bacteria · Nitrates from bacteria · Ethylenediaminetetraacetic acid
Pale and yellow leaf tissues enclosed in greenish nerves	New	Iron	· Fe2 · Fe EDTA · Fe DTPA · Ferric sulphate
Holes in leaves, yellowing and withering tips or edges	Old	Potassium	· Potassium nitrate · Potassium sulphate
Distorted leaf growth, cupped / bent leaf blades. Yellowish edges	New	Calcium	· Calcium carbonate · Calcium nitrate · Calcium sulphate
Yellow spots, similar to Iron deficiency. Yellowing edges while major veins remain green	Old	Magnesium	· Magnesium sulphate
Dead shoot tips and side shoots, brittle stems. Similar to Calcium deficiency	New	Boron	· Trace element mixes
Similar to Nitrogen deficiency	New	Sulphur	· Various sulphates
Dead tips and withered edges	New	Copper	· Copper sulphate · Cu EDTA
Yellowing areas between leaf nerves, starting from tips and edges.	Old	Zinc	· Zn EDTA · Trace element mixes
Inhibited flowering. Similar to Zinc deficiency	Old	Molybdenum	· Ammonium molybdate · Trace element mixes
Stunted growth, darker green leaves. Can be similar to Nitrogen deficiency	Old	Phosphorous	· Phosphates from decaying matter · Potassium dihydrogen phosphate

Useful Glossostigma elatinoides links

Setting up a glossotank
Glossostigma elatinoides fan club
Glossostigma elatinoides
Glossostigma photos
Glossostigma pots
Glossostigma elatinoides cultivation

Conclusion

I hope my article on Glossostigma elatinoides i useful for whoever might want to give it this creeping beauty a try. Patience and passion is the key to success. If you have any suggestions or you want to correct any errors in this article, please write to aen@aendirect.com with your valuable comments. Thank you.