chapter4

A fish only system is easy to define. It is a system which is home to, that’s right you’ve guessed it - fish only - no corals.

It could possibly have invertebrates in there as well - shrimps, snails etc.

In a fish only system you need to concentrate on the habitat and requirements of the fish which will be under your care. Fish, similar to corals require stable conditions, room to swim and plenty of hiding places.

There are, however two types of fish only systems which are determined by the biological filtration system in use. These are classed as:

  • Fish Only
  • Fish Only With Live Rock

Let’s go into these in a little more detail.

Fish Only

In a fish only (without live rock) system only inert, non living ecor is utilised. The filtration for the system is provided by powered man made filters such as fluidised, canister, trickle etc.

Many of this type of aquarium have a mixture of manmade filtration systems.

The biggest advantage of this type of system is that if a disease was to occur then copper based medication could be used. This type of medication cannot be used at all if live rock, invertebrates are in the system. The animals which exist within the live rock and invertebrates are highly sensitive to copper and will die when it is added to the aquarium.

In a fish only system you also have the opportunity to keep large, aggressive and destructive species if you so wish - including those that have invertebrates as part of their diet.

Fish Only With live Rock

This is a type of system which is starting to grow in popularity especially to aquarists who prefer to have a more natural looking aquarium. With this type of system not only do you achieve a more natural looking aquarium but you are also still able to keep fish species which may be incompatible with some invertebrates.

The biggest benefit of this system is the live rock, with its very good filtration capabilities, ensuring that with the proper maintenance and care some important water parameters will remain stable.

Invertebrate life forms will come on the live rock when it is purchased, however this type of system allows for the introduction of invertebrates into the system - but only invertebrates which will not be harassed or eaten by the resident fish.

In this type of system you will not be able to treat disease with a copper based product as this will kill all invertebrates, however you could and should implement a quarantine tank system which can also double as a hospital tank should the need arise. This is discussed later on in the guide.

The good news is that it is quite straight forward to convert this type of system into a fully fledged reef aquarium in the future if you so require.