Aquascaping Adventures 2011

Bringing deserts and tropics into the northern temperate.

We are certainly not experts, but have successfully run a number of tanks/aquariums, of which our two most recent are a small tropical tank for tetras, and a larger coldwater tank for danios, minnows and fantails. These prevented us from keeping some of the more extravagant tropical fish, which are too large to fit in the smaller tank, but need warmer temperatures than the bigger tank. This page documents our most ambitious tank, designed to cater to the larger tropical fish. It's nothing compared with some of the more advanced marine setups, but it's something within reach. The information is provided here mainly so that others who are interested can see how to recreate some of the parts that they may want to copy. Yes, there's a lot of text, but each section also has pictures, if that's all you're here for.

The tank was set up as a tropical freshwater tank, with the conditions and layout designed to suit the needs of its intended inhabitants. The places to hide, the sand for digging, the planting around the edges with open space in the middle, the mix of tall grasses and broadleafed plants, the expanses of rock surface, the water depth, the aeration and other water conditions. All of these help to provide an environment suited to the specific community of fish.

Our nearest suppliers are all members of the ubiquitous Maidenhead Aquatics franchise, so many items were purchased from their shops.

Tank and cabinet

First things first, the tank. We chose the AquaTropic Pro 1200 (120 cm x 65 cm x 43 cm external, approximately 116 cm x 41 cm x 54 cm internal). When filled, it holds a maximum of 253 litres of water (56 Imperial gallons, 67 US gallons), though the substrate and ornaments leave it with a usable volume of about 230 litres. It comes with a cabinet, Aquamanta EFX 300 filter and Interpet Deltatherm 300Watt heater (though due to a thermostat failure, that was replaced with a SuperFish Combi-Heater 300 W heater). It has holes in the top for the intake and outlet, and does not have any inbuilt pipes that get in the way of any backing sculpture. The relatively large size - significantly larger than most beginner tanks - is intended to allow a variety of different species to be kept in their ideal numbers. It also makes it easier to keep the chemical balances stable. To reduce algae growth, we replaced one of the Anubias T5 10000K white lights supplied with the tank, with an Arcadia T5 Plant Pro light. An additional couple of red Aqua-Brite LED lights powered through a 4-Way USB Power Hub allow us to watch the nocturnal pleco.

It would have been possible to buy a lower cost tank, such as the Fluval Roma 240 or Aqua One EuroStyle 100 or Aquience 1000R (the Juwel Rio 240 was in the same price bracket as the AquaTropic Pro tanks). However, these either did not satisfy the dimensions we were looking for, or had badly placed fittings that prevented the sculpture from being placed correctly. Maidenhead Aquatics also offer custom-sized aquariums with elegant cabinets, but the cost of these is significantly higher, and the openings in the top of the tanks were far too small to allow any large sculptures.

The substrate is Unipac's Tana Aqua Sand, and needed about 14 kg to cover the bottom of the aquarium to a depth of 2.5 cm (not including the area occupied by the sculpture). 4 litres (roughly 5 kg) of JBL Aquabasis Plus was also laid under the areas that would be planted, as well as around the cliff-ledge plants. No doubt it will not remain in place very well...

The tank was put through a fishless cycle to prepare the filter bacteria before stocking with fish. Although it is possible to use rotting fish flakes or rotting prawn meat to start the cycle off, it was quicker to bypass the rotting stage, and just put ammonia directly into the water. The tap water was conditioned and seeded using the reliable Nutrafin Aqua Plus and Cycle. (We did initially try JBL FilterStart instead of Nutrafin Cycle, without any significant effect.) The cycle took 25 days in total.

Note that the ammonia is much stronger than the instructions expected, and even with only a quarter of the stated dose, it was nearly four times the required value, and was enough to kill off a set of plants. Oops. With the ammonia in the bottle at 9.5% w/w solution, it needs only 1.05 ml to get about 1 ppm in a tank of 100 litres. The form below calculates how much of the ammonia solution needs to be added:

Ammonia calculation tool
Amount of ammonia solution to add

[amount] = ( [desired concentration] x [tank volume] ) / ( 1'000'000 x [ammonia concentration] ) (click for units)

In the same units as [tank volume], eg. litres - multiply by 1000 to get from litres to millilitres.
[desired concentration]
In parts per million, eg. 5.
[tank volume]
In the same units as [amount], eg. litres.
Compensating for the concentration being in parts per million.
[ammonia concentration]
As a decimal portion, eg. 0.095 - divide by 100 to get from percentage to decimal portion.

For testing the cycle, we had test strips for pH, ammonia and nitrites, multi-test strips for just about everything, and a testing kit. The testing kit is the most reliable, but needs the chlorine test from the multi-test strips, and does not have a high enough range of nitrite and nitrate detection to match what we encountered during the initial cycle. The nitrite and multi-test strips offered better ranges for nitrite and nitrate respectively. The dedicated ammonia and pH test strips were too inaccurate to be of any use, and typically gave wildly incorrect readings. Alternatively, the JBL test kits are by far the most accurate we have used, but are quite slow to show results, and do not have enough range on the nitrite test to cope with the values we experienced. Their 6in1 test strips give a high enough range on the nitrite, and could be used to compliment the test kits.

Several other minor parts were needed, of course, such as thermometer, light timer. On hot days when cooling is needed, a small fan can be hung above the tank on hooks. Power for the tank is supplied through a surge protected extension lead, with the light timer powering a double-socket extension lead for the two light plugs (it's not advisable to have an extension cable powering an extension cable, but the total power usage is well within the limits).

The cabinet doors needed door buffers to make them close more gently, and the feet needed plastic wedges (old credit cards...) to level them out, but other than that, the cabinet seems good enough. To make best use of the space in the cabinet, we built a very basic free standing shelf, with legs made from 34mm x 34mm timber, a shelf and lid made from MDF and chipboard scraps (with the shelf held to the legs using rigid joints), back and side panels for the shelf made from hardboard scraps, rubber cushioning feet, and thin strips of timber extending forwards to allow hooks to be added to it. It is sized to leave a small gap all the way around it to avoid it shaking due to the filter and air pump vibrations, and is not attached to the cabinet to avoid damaging it. It is probably the ugliest shelf in existence, but it serves the purpose, and it is hidden from view in in the cabinet.

Mountains and rocks

The mountain ornament is the Clearstream Aquatics "rock strata & caves" ornament. There are several similar variations - ours is the one with the code HHB016. Whatever that means.

The cichlid cave is the Clearstream Aquatics "cichlid cave sm" ornament, code HSY079S.

The other mountains are simply pieces of "elephant skin" rocks, from Maidenhead Aquatics. They also supplied the cobble stones. The quartz pebbles were sourced from a garden centre.

The volcano is the Arcadia Classica Aqua-Brite Volcano Aeration Ornament, which comes complete with its own air stone. Along with that, we picked up a red Aqua-Brite LED light, which fits inside the volcano to light it up, and is powered through a remote controllable switch. Air is supplied by a TetraTec APS300 air pump, which is regarded as one of the quietest pumps available (though "quiet" is a relative term). Air pipe, suction cups and Hagen Elite Aquarium Airline Check Valve were obtained separately.

To make the air pump even quieter, there are suggestions to put it on a sponge or hang it from elastic to reduce the transfer of vibration. In this case though, it is the body of the pump that shakes and makes the sound. Another suggestion was to suspend it in a jar by its wire with a small hole letting in the air. However, that does not work well with such a large pump, and would not allow enough air in to keep the pump cool. In our case, it was better to construct a box with a simple labyrinth shape. The pieces of scrap chipboard are screwed together, with old carpet stapled to the inside. It has rubber cushioning feet, a hinged lid, and a drawbolt/toggle latch. The shape reduces the sound significantly, with the carpet preventing reflected sound from travelling around the corners of the labyrinth, and with the gap also allowing plenty of air in. For louder pumps, the labyrinth could be made to turn more corners, and extra carpeting (or even acoustic carpeting) could be added.


Because we can't all make our own moulded polycarbonate ornaments...

The sculpted rock backing is by far the biggest experiment in the tank, and was custom made to suit the tank. The procedure for making it was taken from a series of instructional videos; 1 2 3 4 5 6 7. Essentially, it is layers of styrofoam cut to shape, glued together, melted slightly, and coated with coloured cement. The process took just over 5 weeks from the delivery of the tank, to having the sculpture completed, installed, and ready for the tank to be filled. Most of that time was spent waiting for various glues and coatings to dry.

The sculpture is intended to be 37.5 cm high (needing 15 layers of styrofoam), 44 cm long and 39 cm wide, shaped so that it fits through the openings in the top of the tank. 3 sheets of 60 cm x 125 cm x 2.5 cm styrofoam were used. It intentionally covers less than half of the tank, to provide different environments in different parts of the tank - it could be made in several pieces that cover the whole back, if needed. The design is loosely based on the features of Jabal Al Qarah and the Tweig Escarpment on the Arabian Peninsula.

Cement/mortar (used to coat the sculpture) is one of the least fish-friendly materials, creating an extremely high pH - as strong as bleach. It's not something you want to put in a fish tank. Even after curing, it can still leach toxic chemicals for several months. No matter which option you use, having cement in the tank requires carefully monitoring and adjusting the pH for several months. The options are:

  1. Use a sealant on the outside, such as pond sealant. This does not cope well with a flexible material, and also will not seal the back of the cement surface, so limited leaching will occur. It also melts styrofoam. Alternatives that are not specifically designed for the purpose include spray-on grout sealer (as long as it is safe for aquariums), epoxy resin (which must be applied only to a completely dry surface), or water-based acrylic lacquer.
  2. Use a waterproofing agent in the cement mix. This can prolong drying and curing times, but is a reasonable solution as it reduces the leaching. However, many waterproofing agents contain harmful chemicals of their own, so only use one which claims to be safe for aquariums. Note, however, that they will not remove the harmful chemicals from the cement, and fish may still be affected by them.
  3. Instead of cement, paint the sculpture with epoxy resin, and cover it in sand, repeating the process to get the desired finish. This produces a very natural finish, but is expensive and difficult to perfect.
  4. Instead of cement, cover or replace the sculpture with fibreglass. This is a significant undertaking, as it requires working with hazardous chemicals, but the end result is harmless. In addition, a fibreglass sculpture can be mounted in an already-filled aquarium (using suction cups or just gravity), and removed at any time.
  5. Instead of cement, replace the sculpture with dinnerware-safe pottery clay, which is then fired. This can also be mounted in an already-filled aquarium, but requires access to a pottery kiln, which must be large enough to contain the sculpture. This approach prevents the use of styrofoam as the core of the sculpture, as it cannot withstand the heat of a kiln.
  6. Use a dedicated aquarium/potable water cement. In the USA, one option is SikaTop Seal-107, but the cost of this is prohibitive in the UK. An alternative is the Aquarienmörtel from Zoo Zajak. These both have the advantage that harmful chemicals are kept to a minimum, though there is still the possibility of limited leaching. The Aquarienmörtel uses a large grain size to reduce leaching, resulting in a very rough (but natural-looking) texture.

We went with the last option, sourcing our aquarium cement from the German company Zoo Zajak. Around 0.5 kg of raw material was needed for the three layers covering the sculpture, with 1.1 kg used in total, including test pieces and the wasted cement that was thrown away after preparing too much. The shipping cost was surprisingly low, and the language barrier provided only a little entertainment. It certainly helped to have friends who could ask the special-case questions in German, and translate the answers, and for that we are most grateful. The answers are included below.

According to the instructions, it does not need any additional sand, and can be dried in 24 hours at room temperature, after which it needs to be immersed in a fresh water bath for 2 days to remove excess lime. According to the supplier, however, it is best dried slowly over 5 days (with wet towels keeping it humid for the first 3), to improve the strength. To avoid upsetting very sensitive fish, after drying it should ideally be cured in a bath of weak ascorbic acid or citric acid at about pH 5-6 for anywhere between a few hours and a few days (depending on the thickness of cement). After that, it would need 2-10 days of fresh water baths (changing the water once per day) to remove any remaining chemicals. It's best if curing can be done outside the tank to allow any acid-damaged areas to be re-applied before placing it into the aquarium. We put it in a large plastic box and used an empty filter to sprinkle the acidic water over it - it's also possible to hold the sculpture underwater using netting (though the netting may damage the surface) or just push it underwater using the box's lid.

The cement is dyed using buff, red and black cement dyes from Wickes. (These can also be added to white acrylic paint to allow for touching up damaged parts, but need to be mixed much darker as the cement will darken when immersed or coated with sealant.) After curing and drying, some acrylic paint was used to produce the white, as it is not possible to produce pure white cement that is safe for aquariums.

The cement does not stick as well as you might hope in such thin layers (it is designed to be used as the sculpture material itself, not to coat a sculpture), so we found it useful to apply a sealant afterwards, to prevent it from flaking or crumbling off, or being bitten off by destructive fish. Pond sealant sounds like the right thing to use, but the solvent melts the polystyrene wherever it manages to seep through the cement. The best approach is to paint it with a clear, cold curing epoxy resin such as the Vosschemie Glosscoat, even if it does seem expensive. It needs to be mixed in relatively large amounts (200+80 grams minimum) and stirred for at least 5 minutes before application, or it will not generate enough heat for it to cure properly. It only gives 30 minutes for application - after that, any remaining resin in the mixing pot will suddenly become excessively hot, and cure in a matter of seconds. Once applied, it should be left to cure for a whopping 8 days at room temperature, or as little as 6 hours in front of a 50°C heater (anything above 70°C can damage the styrofoam).

The sculpture was glued using clear aquarium silicone sealant, available from most fish tank suppliers, requiring just under one 310 ml tube to hold it together, and another 310 ml tube to hold it into the tank and bead the edges. Pretty much any aquarium-safe brand will do. It's worth noting that even with 0.5 kg of cement and 150 g of epoxy resin pulling it down, the buoyancy of the styrofoam still produces several kg of upward force that the silicone has to counteract. In our case, this is a little under 13 kg of upward force. No matter how accurate the shape may be, the gap between the sculpture and glass can become significantly wide in places, so using an entire tube to hold it in place feels justified. Beading is painstaking with such complex edges (why oh why didn't we keep the edges straight?), laboriously pushing the silicone into place with wet fingers. In theory leaks in the silicone (or epoxy) should not be a problem, but it is possible to fix any leaks after the tank is filled by using an underwater setting silicone (though this is significantly whiter than regular silicone once cured). Since the messy silicone and styrofoam could be seen from outside the side of the tank, the outside was covered up with some aquarium background film, facing outwards and held in place with blu-tack.

Several tools were needed to make the sculpture, including: coloured permanent markers, modelling knife, blow torch, (silicone) cartridge gun, set square (with a hard edge for cutting against), a pair of clamps, sandpaper and a wire brush for keying surfaces, a heater for the epoxy, fan for the silicone, and copious quantities of kitchen towels. To apply the cement, some paint brushes and makeup sponges were used, as well as a spray bottle of water. The epoxy required a few disposable brushes. Ideally, the glass should be cleaned with vinegar before siliconing, and some white spirit can help to remove accidental drips of silicone from the aquarium glass. Other things to consider are surfaces for cutting, gluing and melting, protective gloves, pots/jugs for mixing cement and epoxy, paint remover for the brushes, and the partridge that is still stuck in that pear tree after 12 rounds.


To aid in the choice of fish, we used the book An Essential Guide to Choosing Your Tropical Freshwater Fish (ISBN 13-978 1902389 95 0). The final choice was:

After the fishless cycle, the filter bacteria were converting 2 ml of ammonia (9.5% concentration) every 24 hours. At that rate, we could almost have stocked the tank at once. To be on the safe side, we added 5 fish at first, and another 5 after a week. In between, to sustain the bacteria, we steadily increased the amount of daily food so that by the time the second set of fish arrived, there was no extra amount of food needed to supply them. Technically this would count as overfeeding for a week, but we needed to retain the bacteria that had built up in the filter, and it helps to avoid the shock when additional fish are added. In most of the subsequent cases, the percentage change in population would be relatively low, so the overfeeding approach is not needed.

In most cases, the fish were obtained from Maidenhead Aquatics. The only exception is the tiger plec, which was obtained from the specialist shop Aquabatic.


The tree is made from a Java fern attached to a conveniently shaped piece of bog wood. Initially it is tied in place with thread until it has had a chance to root itself. Most other plants are either held in place with thread, or buried in the substrate and underlying plant feed, and held down if needed with pebbles. The Java fern tree is the only plant to survive the high ammonia levels, so even though it looks a little unhappy, we did not want to remove it. Hopefully it will recover fully.

The plants are as follows:

The plants were selected to make the fish feel more comfortable, and help to reduce the unwanted nitrates, maintaining good water quality. Several of the faster growing plants also help to hide various pieces of hardware. There could be more (a moss carpet would be nice on the left) but it would then need a dedicated CO2 source.