How to set up a Cryptocoryne aquarium

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Cryptocoryne is one of George Farmer's favourite genera of aquatic plants. Here's how he set up a large aquarium using crypts exclusively in a large low-maintenance aquascape.

While serving in Afghanistan for a few months I had time to consider what type of planted aquarium layout I would set up on my return. Having judged the 2008 AGA International Aquascaping Contest I had also gathered plenty of inspiration…

A friend had donated a 370 l/81 gal aquarium, so I wanted something relatively low maintenance. I did not fancy 50% weekly water changes and, being a tall tank, maintaining fast-growing carpeting plants would not be an option. It would be awkward to reach the bottom, even though I am over 1.8m/6’ tall.

I wanted slow growing plants that required little or no pruning and lower light tolerance, so I could easily manage nutrient dosing, even in my absence. I did not want Java ferns or Anubias as I have used these so many times before.

I considered Amazon swords (Echinodorus) but these can be quite fast growers and soon overtake the largest of aquaria without frequent maintenance. The logical choice was a tank full of Cryptocoryne, commonly known as crypts. They fitted the bill perfectly.  

They are low light tolerant, slow growing and, with many varieties available, would provide ideal foreground, midground and background interest with pleasing blends of colours, forms and textures.

I intend to keep this layout for at least 18 months, so it will be interesting to see how it develops.

The set-up

The aquarium is a Rena Aqualife 120 complete with cabinet and lighting. I swapped the supplied T8 lighting, removed the hood flaps and replaced them with the new Arcadia OT2 luminaire fitted with 4 x 54w HO T5 Plant Pro lamps that give a pleasing colour rendition.

This is enough light to grow most plants, but I decided to use two tubes instead of four to encourage slower growth and less maintenance. These days I prefer lower lighting levels to grow my chosen plant species, as it not only gives me less work to do with nutrient management and plant maintenance but saves electricity.

I decided to avoid CO2 injection as it also helps keep down growth rates, helping reduce maintenance. Instead I am using Easy-Life Easycarbo as a source of carbon supplementation to help maintain healthy plant growth.

In combination with Easy-Life Profito and Tropica Plant Nutrition these three products work well together. As a lower light set-up with a nutrient-rich substrate (ADA Power Sand Special and ADA Aqua Soil Amazonia), adding nitrates and phosphates to the water column is not necessary for at least the first six months.

The Rena tank is supplied with a Rena XP3 filter but this was missing from the set-up. Instead I am using two JBL external filters with a combined claimed flow rate of 2,400 lph.

I replaced much of the sponge media with mature ceramic media to allow for quicker bacterial colonisation that helps keep initial nuisance algae at bay. This also allowed me to stock an algae crew consisting of a few Siamese algae eaters (Crossocheilus siamensis).

Fish selection

My intention was to set this tank up for Discus, but decided that the South-East Asian planting suited different display fish. I opted for some wild Rosy barbs that PFK ‘s Jeremy Gay supplied.

Their subtle coloration, shape and size suit the aquascape very well. An algae crew consisting of Siamese algae eaters, Bristlenose catfish and Cherry shrimp ensure that the crypt leaves, wood and aquarium glass are kept spotless.

Six Botia striata ensure snails are never an issue and I will probably add some more small display fish to complement the barbs some time in the future.

Crypt melt?

Crypts can be sensitive to slightest changes in water parameters. Leaves disintegrate, leaving holes or missing portions. The entire plant may turn to mush — and this is crypt melt.

Usually new leaves generate so try to keep conditions as stable as possible, such as temperature and nutrient levels.

Big water changes, if carried out only sporadically can trigger crypt melt, as can changing your liquid fertiliser or CO2 dosing.

It’s pot luck!

There is an element of luck when buying some crypts. They are usually supplied in emerged form and change leaf shape and colour after adapting to their submerged existence.

This appearance depends on growing conditions such as lighting and nutrient levels. My Cryptocoryne wendtii 'Green' will be bright green with smaller leaves in my high light tank with CO2 and lean substrate, but will grow larger, browner leaves in my larger aquarium with nutrient-rich substrate.

Tank specifications

Dimensions/profile: Rena Aqualife 120 x 120 x 50 x 60cm/47 x 47 x 20 x 24”, 371 l/82 gal.

Filtration: 2 x JBL Cristal Profi 500 external canister filters.

Lighting: Arcadia OT2 luminaire (4 x 54w HO T5), Arcadia Plant Pro lamps, 2 tubes 8-hour photoperiod.

Substrate: Zambezi gravel, silica sand, ADA Power Sand Special, ADA Aqua Soil Amazonia.

Fertilisers: Easy-Life Easycarbo (4ml per day), Easy-Life Profito (2ml per day), Tropica Plant Nutrition (2ml per day).

Maintenance: 25% water change every 10-14 days, filters cleaned alternately every four weeks.

Hardscape/décor: Petrified wood, Irish driftwood.

Plants: Cryptocoryne beckettii 'petchii', C. crispulata var. balansae, C. parva, C. undulata, C. undulata 'broad leaves', C. wendtii 'brown', C. wendtii 'green', C. wendtii 'Mi Oya', C. wendtii 'Tropica', C. x willisii.

Fish/inverts: Puntius conchonius (wild), Botia striata, Crossocheilus siamensis, Ancistrus spp., Neocaridina heteropoda var. red.

Putting it all together

1. The aquarium holds around 370 l/81 gal and is relatively tall at 74cm/ 29” including the hood. Overall height, including the cabinet is 146cm/57”, making for great visual impact.

Maintaining the lower levels of the tank is awkward, especially if vertically challenged and a step will be necessary! Two large brace bars also hinder access, but tank quality is superb with flawless silicone work and an excellent overall finish to tank and cabinet.

I would love to see this range produced with OptiWhite glass and clear silicone…

2. A black background is fitted to the rear of the glass. I use olive oil and a credit card to attach the background, smoothening out air bubbles.

Usually I don’t use any background in my aquariums, relying on a pale wall behind the tank and lighting it to create a pleasing effect. However, as the filter inlet and outlets are black I opted for a black background to disguise them. Black also helps to contrast with the colours of the fish and plants.

3. Filter pipework is set up and sand added. I have used very fine play sand in the areas to be left open. Play sand is inexpensive and non-toxic, but requires rinsing to clean out dust and unwanted debris.

At a later date I decided to replace the very fine sand as it requires too much maintenance to keep looking clean. I replaced it with Zambezi gravel (a fairly fine natural-looking grit) as this is easier to maintain and looks great.

4. ADA Power Sand Special is added to the remainder of the tank’s base. This is very rich in nutrients and designed to be added underneath Aqua Soil. Power Sand Special also contains ADA Bacter 100 and Clear Super to aid bacterial colonisation and water purity.

5. Irish driftwood is added first, followed by petrified wood on top to prevent the wood from floating. The wood was donated by Peter Kirwan. Petrified wood, is fossilised wood that is dense like rock. It is relatively pale, consisting of white, yellow and orange hues that are very attractive in the right setting. Petrified wood can be easily smashed into smaller pieces so you can create sizes to suit.

6. Two nine-litre bags of Aqua Soil are poured in over the petrified wood, filling nooks and crannies. This creates a mound shape suitable for plants. Aqua Soil is a superb substrate high in nutrients and creates an acidic environment for roots that crypts prefer. It leeches ammonia for a couple of weeks after installation so do not add livestock until ammonia and nitrite are undetectable with test kits. It is an ideal substrate for fishless cycling as it provides a source of food for the nitrifying bacteria.

7. The tank is filled with water straight from my garden hose clipped to the glass to hold it in position. I use a plastic plate to help prevent water from disturbing substrate. Aqua Soil is very ‘light’ and easily dislodged, so careful filling is essential if my mound shape is to be retained. Once the aquarium is full I added a dechlorinator at the appropriate dose that also deals with chloramine and heavy metals.

8. Smaller pieces of petrified wood are added around the Aqua Soil mound to create an effective unplanted low-maintenance foreground. Initial crypts are planted into the Aqua Soil using tweezers. The pots are all separated into individual plantlets to get the best spread of planting. All plants were supplied by Tropica using their entire range of ten Cryptocoryne varieties. C. balansae is planted in the background and a mixture of C. wendtii varieties in the midground.

9. The remaining Tropica crypts are planted according to eventual size, shape, textures and colour. C. x willisii and C. parva are in the foreground, as these remain smallest. Others are mixed almost randomly, except the background C. balansae. This ensures the layout looks natural when mature.

If I planted in perfect order the result would look too artificial for my taste.

10. Once planting is complete I switch on filters and heater and allow the water to clear. I fit a lights timer to ensure a regular eight-hour photoperiod and add liquid fertiliser every morning. I regularly test water for ammonia and nitrite and, when levels are undetectable, add my initial algae crew. I continue to test for a couple more weeks and add six Botia striata to deal with pest snails and 40-plus Cherry shrimp. After a couple of months I add those wild Rosy barbs.

This item first appeared in the April 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.