Hard decor is possibly the wrong description for this section, maybe environmental features would have been more appropriate, but I want to allow your imagination to roam while choosing furnishings for the tank which not only cater for the needs of the fish, but also create a great looking tank.

The items which you use to furnish your tank should ideally reflect the fishes natural biotope. Only by providing features which occur in the wild will you get the best from your fish.

First let's look at the natural furnishings one can provide.

Wood is a popular choice. Bog wood, driftwood, Mopane wood and dried Beach (strip bark and season for up to one year before use) can all be used safely to create crevices, hiding places and mimic a natural environment for forest river dwelling fish. Always boil the wood for several hours before inserting in the tank. This effectively cleans the wood and in the case of bog and Mopane wood, releases much of the tannins which instantly turn the aquarium tea brown. The tannins will still be released slowly in the tank after boiling and it may take several months before all traces of tannins are unnoticeable, but boiling at least allows you to see the fish during this time. Tannins incidentally, are good for the fish, it's what they experience in the wild. Natural wood is also ideal for acting as an acid buffer. The tannins help soften the water and create a slightly acid pH. Additionally some catfish will gnaw on wood and for this reason I never recommend that one should varnish any wood intended for a fish tank. Be wary of using other types of wood in the fish tank. Some woods may release resins or sap which could be detrimental to the fish and others may rot after prolonged contact with water. Many people use garden canes to mimic reed beds. This is fine but always seal the open end with silicone sealer to prevent rotting from the inside.

Rocks are also a great naturally occurring form of decor but again not all rocks are suitable for the fish tank. Make sure that rocks contain no metals, ask your retailer if in doubt. Rocks which are calcareous (i.e. contain lime) should be avoided as they increase hardness. Tufa rock is calcareous but can be used to great effect in African Lake cichlid tanks. Tufa is soft, easy to cut to gain a desired effect and conversely to wood acts as an alkaline buffer. Slate is also very adaptive and can be stacked to create a wall of caves for catfish or placed on end for terraces and borders.

When positioning rocks, always position them directly on the tank bottom and fill in with the substrate. Siliconing rocks together is also a wise precaution as burrowing fish can create the most catastrophic rockfalls!

We have all seen the jumble of plastic "decorations" on sale at the local pet superstore. Personally I cannot abide shipwrecks, "no fishing" signs, bubbling clams and the worst of all skeletons with moving arms clutching a gold chain. They look awful, do not benefit the fish and in my opinion they are the fluffy dice of fish tanks. However, some artificial items are effective and even satisfy the needs of the fish. Artificial rock and wood now look uncannily realistic. They are also much lighter than the real thing, ideal if you are trying to recreate Lake Malawi in your living room.

Finally, I did say use your imagination when choosing decor. In the show tank you may want the most aesthetic furnishings, in the breeding tank however, you merely want to mimic caves and hollow logs. Try using PVC pipes, up-turned terra-cotta flowerpots or even old video tape cases with the tape and metal parts removed. Yes you read correctly, I know one breeder who swears these are the ideal spawning caves for Zebra plecs (Hypancistrus zebra).