Project Fishy

Sweaty Dave, Going Postal
As shown when purchased

Anyone who has read any of my articles knows I do like a good project. If I know that I’m going to be stuck in the house, looking after kids with bad weather, I need something to do as they just amuse themselves with Xboxes etc.  I did a quick summary of this project a while ago, but have recently found some photos of the construction, so in a similar way to the shunting series, can talk you through what it involves.

A few years ago I decided to find a hobby of interest, that the kids could find interesting too, if not too involved, as at the then ages of 5,8,10 they quickly would become bored.  They always pestered, as kids do at that age for a pet. We both work, so a dog was and still is out of the question – it’d be cruel to have them locked up all day. Neither of us are too keen on cats, and I was looking for something that you could leave for a few days when we went away. Guinea Pigs, gerbils, hamsters – just rodents, nope, so I considered keeping fish. I’d always admired the brilliant colours of marine tropical fish and corals, having snorkelled on the red sea when a teenager had vivid memories of the many creatures on the reef.

I’d had the obligatory goldfish in a bowl when a kid. It survived on tap water and being chucked into the sink when the bowl was cleaned, later moving to a tropical freshwater tank with mini catfish, zebra danios and Angel fish.

Sweaty Dave, Going Postal
Ugly and noisy filtration pipes on the side

There is a hierarchy of difficulty in fishkeeping:

  1. Goldfish in a bowl – tough as old boots, but die pretty quickly.
  2. Coldwater freshwater aquarium – basically a larger version of above, which you take a little more care with, by having an air pump oxygenating the water – it is in a pipe from below the gravel, pulling water up to create a circulation through the gravel which filters waste. These are the fancy goldfish you find at garden centres, usually quite small but with ornate fins and colouring.
  3. Tropical freshwater aquarium – as above, with the air pump circulating through the gravel, but with a heater added, to keep the aquarium at 77F – but they can withstand some variations. The fish are readily available and cheap, the aquarium is usually decorated with plastic lookalike plants (or real ones that the fish eat) and other scenes. Tanks are normally around the 24in to 36in width, 18in tall and 12in deep – so around 30 to 40 gallons, weighing around 150kg. Lighting is simply enough to let you see the fish. The only maintenance is occasionally cleaning the crud from the gravel in the bottom.
  4. Tropical marine aquarium – These come in a number of variations – each more difficult to achieve with cost escalating in a similar way.
  5. Fish and soft corals – this is the starter version, but still a magnitude more complicated than freshwater
  6. Fish and hard corals – this requires much more light and power and hard corals are now very hard to come by
  7. Zero nitrate tanks – basically no fish to ensure water is extremely pure, for some special corals.
  8. Nano tanks – these are small usually 1 or 2 gallon tanks you often see in Garden centres. Due to their small size, they are very difficult to keep stable – swings in temperature or water chemistry will kill the occupants.

Having had 1 and 3, it was time to go for 4. The plan was to start initially with 4a and move on with experience.

A tank of this type is a significant challenge. The trick is to maintain an environment that is stable, in temperature but also salinity (how salty it is), and levels of various chemicals – oxygen, nitrates, nitrites (both waste products of the fish and organisms, magnesium, potassium and trace elements. To do this, a marine tank requires a secondary tank usually hidden in the cabinet below, called a sump which acts as the filter. As with many such things, the larger the setup, the more stable it will be. To embark upon this needs a few key factors in place – firstly lots of cash, as there are many many gizmos and supplies needed and the larger the setup. You also need a local supplier – buying a live fish over the internet will be a gamble to see if it arrives alive. When I started this in 2008, there were three or four good suppliers in the local area. The subsequent recession wiped them all out as the expensive hobby is the first thing people cut back upon. Only the large Dobbies nearby has a small amount of coral and fish.

Sweaty Dave, Going Postal
The sump in the cabinet below

Did I mention size? One of the reasons that marine tanks are big is to satisfy the rules of ‘fish inches’.  The amount of fish an aquarium can hold is dependent upon the surface area of the water. This is as that area determines the amount of oxygen that is taken into the water, known as gas exchange.  If you have a tall thin column of water with only a small surface area at the top, it would contain very little oxygen.  Even adding an air pump and bubble stone does not make much difference as the bubble is in contact with the water for a short time. For freshwater fish, the rate is about 30 inches of surface area per inch of fish, for marine it is 48 inches of surface area per inch of fish.  As an example a 24in x 12in tank (regardless of depth) has a surface area of 288sqin so can hold around 10 inches of fully grown freshwater fish or 6 inches of marine.

So with that in mind I started to look at options. New tanks were available but anything of a decent size was around the £1500 mark just for the tank and cabinet. Add the other kit and it’d be another £1k before you look at the contents (another £1k). Time to find a cheaper option.

Ebay is a good place for those aquarists that have fallen by the wayside, putting a track on local aquariums soon showed up a suitable tank – about 50 miles away, measuring 7ft x 30in deep x 30in  tall with 24inx12x12 sump tank below a total of 120 gallons – a monster! I won a bid upon it of around £300. It was set up as a marine tank including a sump but had most of the gubbins on show – dominating someone’s home. It took two trips to get it home – the heavy tank itself then another trip with the supporting cabinet.

Mrs SD was less than happy to see it taking up much of the garage – I’d mentioned getting one, but not the size…

Next episode – time to convert it into a decent marine coral reef tank.


© Text & images Sweaty Dave 2018

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