Cycling and Adding Fish

Cycling Your Tank:

It’s time to think about your grand design idea! Be as creative as you like with placing your decorations and the colour of your sand! In other words set up the tank of your dreams. You can of course add decors at any time but I prefer to have as much of it as possible set in the tank before I start. This is because all the surfaces in your tank will house beneficial bacteria colonies that will be doing all the magic. Turning harmful Ammonia and Nitrite to less harmful Nitrate (known as the Nitrogen Cycle) however, the major source for these wonder bacteria is your filter.

When you go with 2 filters these colonies will be split between the 2 filters in 50-50 proportions. There are 2 main methods you can use to cycle your tank, either using a hardy and cheap fish to kick off the process by producing waste and thus Ammonia or the much more preferred and humane way of fishless cycling. If you haven’t got a bucket specifically for your aquarium get it now before you start the steps.

The process:

  1. Clean your tank on the inside and outside with warm water and a clean never used sponge. NEVER use detergents or household cleaners.
  2. Add your substrate. Then fill up your tank about 50% of the way. (note: rocks replace the weight of water so if your tank is filled to the brim it will spill over)
  3. Add your rocks and any other decorations such as plants. Connect your filter hoses and have it ready according to manufacturer instructions but don’t turn it on! Place your heater and set it to the desired temperature of the species of fish you are keeping but again don’t turn it on.
  4. Fill the tank up to the top leaving a gap of 2cm to allow water to exchange with oxygen at the surface. Now connect your lights as well as air pump and turn everything on. (note: some filters will require manual syphoning. Fluval have a valve you move up and down to syphon. If your filter requires this method do it before you turn it on as you will damage the filter running it dry)
  5. Now that everything is on. Leave the tank running for few days to troubleshoot any issues and discover any leaks. If everything is fine then proceed to the next step.
  6. The water you add to your tank must be de-chlorinated and free of other harmful metals and substances. Most LFS will have a good range of water conditioners which will remove all the nastiness from your tap water. Fluval’s AquaPlus Water Conditioner also helps coat the gills and scales of the fish for added protection. You would of course de-chlorinate the tap water before adding it to the tank if you already have fish in there but otherwise you can treat the water once in the tank.

The beneficial bacteria will have already started growing but you can now use chemicals such as Bio Boost to speed up the process as left alone it can take up to 6 weeks for the nitrogen cycle to finish. You can find bacteria and Bio Boost bottles at your local pet shop which introduce a controlled amount of waste and bacteria (follow the instructions on the bottle) to your water which help the nitrogen cycle along. Through out this process you need to do lots of small water changes. Daily water changes of 10-15% will be a good start unless otherwise stated by the bio boost chemical you are using.

At this point it is a good idea to start thinking about the water parameters required by the fish you want to keep. Some fish such as African Cichlids prefer hard water with a higher Ph (7.8-8.5) other tropical fish prefer very soft water specially if they come from river systems. You should think about methods to safely alter your water chemistry. Some people are lucky to have the correct water right from the tap! Ocean Rock and Limestone are popular in African Cichlid tanks to buffer the PH and add hardness while driftwood and live plants are popular in most other tropical tanks.

Throughout this process you need to be monitoring your water parameters to see how all your hard work is paying off or if it isn’t. Check for Ammonia, Nitrite and Nitrate levels and they should be dropping in numbers until they reach 0 (in the case of Nitrite as it’s the least toxic of the lot it is tolerated in amounts of up to 20ppm but never more than 40ppm). This method usually commences in 2-3weeks but can take longer or less.

Adding fish:

Now that you have spent ages getting your water parameters to be perfect it is finally time to add fish!

African Cichlids –

This can be tricky with ACs. Normally you want to add 1 fish of a decent size (5cm) or up to 4 small fish to a newly cycled tank then go back and buy more after 2 weeks of smooth sailing and non-fluctuating water parameters. Due to the aggressive nature of these fish however, you need to add more than 1 fish. Go with 6 fish (start with juveniles, isn’t it more fun to watch them grow?). 6 fish can be a lot to handle for a newly cycled tank so you will need to check your water regularly (every day for peace of mind) and do a 20% water change twice a week. If you have any spikes in Ammonia, Nitrate and Nitrite you need to do a water change of 50-70% immediately.

If your water is testing great after 2 weeks you can add more fish! African Cichlids need to be added in groups as a single addition may be targeted and bullied to an eventual death by the established fish in the tank. So go with adding another 3-6 fish and continue monitoring the situation as you go along. In theory you can add fish every 2 weeks till your tank is fully stocked given that you maintain water quality, there are no disease or parasite out breaks in your tank and the aggression isn’t such that 1 fish is killing all the others. Provide plenty of rocks and hiding places especially if you are going to keep Mbunas as they are a rock dwelling species and can become territorial.

Be prepared to remove any fish if they are being beaten or being chased non stop and forced to hang out at the top of the tank (this means they can’t hold any territory along the bottom). Alternatively you can choose to remove the aggressor. The stress caused by the non stop chasing and being nipped at will only result in death. The occasional chasing and displaying is normal cichlid behaviour and is part of the reason they are of interest to hobbyists. Choose with care and reap the rewards of these beautiful and colourful fish that will be a great addition to any home! It may seem like a daunting task but honestly when you break it down in steps it is as easy as anything and you get watch them grow and be a part of your personal life and “beg” for food every time you walk past the aquarium.

Note: Keeping African Cichlids should be fun and amusing and when it comes to finding the fish that are suitable with each other for your tank, you should be aware of the fact that not all the fish you put in the tank will get along, sometimes one fish will become too big and aggressive for your tank size and will cause trouble for the other fish. Re-homing fish is common in keeping AC, as they grow and develop, changes in their behaviour are common so to keep the balance you may have to make some changes! Most LFS are more than happy to take them off your hand if you can’t give them a new home. The good news is when your tank and tank mates have settled you can sit back and enjoy and feel worthwhile.

Click here to check out my page on the cichlid species found in the 3 rift lakes to get an idea of the fish you would like to keep and to find out more about species compatibility and how to reduce aggression.

Other Tropical and Cold Water Fish –

Start by adding a group of 4 fish if you are going for small species such as Platy fish, 6 if you are adding really small fish like Neon Tetras and 1-2 if you are adding bigger fish such Central and South American Cichlids or Discus. Size really does matter. By increasing the biological load in your tank slowly you are giving your filter and beneficial bacteria a chance to catch up to the increased waste produce. Things are a little simpler when it comes to most other aquarium fish. The majority of the popular fish are relatively small in size and easy to mix; having said that there are exceptions.

Not all fish can be mixed together for example 2 male Siamese Fighting fish will fight to the death if housed together. Central and South American Cichlids are territorial and if enough space and hiding places is not provided it can end in disaster. It is a good idea to house 3 females per 1 male of most species to avoid a single female being harassed. Of course relative to your tank size and decorations this may not be an issue as any fish being harassed will be able to break line of site and/or take a breather from the aggressor. You may want to avoid breeding in your tank in which case you are better having all males or all females of the fish you want to keep. Left to their own devices and the correct conditions more often than not they will breed all on their own.