. What a handsome chap!!

This was end of April Dexter still has his full winter coat on .

Taking five 

Tropical freshwater fish (plus some Amano shrimps and a few Nerite snails).

I used to keep tropical fish in my teens, but when I moved from home it was too difficult to have aquariums in rented accommodation and so I sold all my stuff. And then when I eventually became a home-owner I thought about it again, but was travelling too much and really didn't have the time required. I always planned to put a big tank in the office of my company, but so far it hasn't happened (but maybe it will now). And then, during an enforced break in travel (due to COVID) I decided to set up a tank here in Germany.

My original interest way back was in Amazonian 'blackwater' environments and so I decided to do the same again. The big difference is that in the intervening decades, control systems have become more sophisticated, and available. So, having set the basic hardscape and planting, I built a control system to regulate pH, as well as temperature, lighting and aeration / CO₂ concentration and water level so that the tank can be left to its own devices for several weeks.

The environmental design is kind of based on the flooded forest areas of the tributaries of the Rio Negro (although with slightly denser planting for aesthetic reasons). Only one species of fish is present, Nannostomus marginatus (the Dwarf Pencil Fish). It is impossible to get Amazonian Glass Shrimps at present and so I compromised with Amano Shrimps, which are similar in appearance and temperament. A few Nerite Snails keep the glass mostly clean, but the pH is really a bit too low for them.

The tank was set up in the early summer of 2020 and the first shrimps and snails were introduced after about 3 months. The fish (20 of mixed ages and sex) were put in in early Spring 2021 and had to be ordered as they are a less common variety. Over the last year, 3 have died of apparent old age and, although they can be tricky to spot, several individuals have been exhibiting breeding behaviour. That led to one (possibly two) young survivors that now mingle with the 'grown-ups'. The picture below was taken just after some maintenance (the tank had been left to its own devices, on 'automatic', for nearly a month) and afterwards, I spotted two, 8 mm-long juveniles predating on microscopic zooplankton on the mosses. That is encouraging as it suggests that the environmental conditions must be about right.

Today, I did a water change, cleaned / replaced some filter elements and made a modified pair of lids to accommodate the auto-feeder better. I am not a big fan of changing the water too regularly and prefer to get the environmental conditions correct and keep the fish population to a more realistic density. So I only make a change of about 10 % every 6 - 8 weeks using deionised water. There is a dosing system that adds nutrients for the plants every 2 weeks, and I top up the leaves / pods etc every now and then. The plants get trimmed about every two weeks and the floating species (both Limnobium and Salvinia) and get 'culled' weekly and the long roots (of the Limnobium) cut back when they reach the soil. I remove the Limnobium to a small holding tank when we're away for more than a week otherwise it takes over!

The basic aquarium is a Juwel Lido 120 (litre). I really like deep aquariums as they allow one to be more creative with hardscaping than with the more conventional rectangular ones. They make a 200 litre version, but it was just too large for the room (and allow the speakers to be placed where they need to be!). As you can see from the picture, there is a fair amount of wood in the aquarium and it is designed to simulate the tangle of roots and branches one finds in a flooded forest (there is a large piece of wood at the rear too, which provides a cave system for the shrimps and fry to hide out in). There are also some volcanic rocks embedded in the ADA Amazonas soil to help with the structure, although they are barely visible. The roots hanging from above are supported by an aluminium gantry under the lid and can be lifted out if required (i have done this once). The gantry also supports the pH probe, nutrient injection pipe and infrared water level detector (and the feeding ring if it ever turns up!).

Although the Lido comes with a self-contained filter system that contains a heater / thermostat and re-circulation pump I have combined that with external control systems (modified units from Aqua-Medic). The temperature is controlled by one of their units and sensors which allows me to add cooling (via evaporation fans) when needed and the internal thermostat is set 3 degrees higher than the maximum control temperature to act as a safety system. I did use an external filter during the first few months to speed up establishment, but have reverted to the internal filter system and pump (with an additional screen on the inlets), which I find works perfectly. The pH is maintained at about 6.2 during the day by CO₂ injection using a solenoid valve / regulator unit from CO2 Art in Ireland and is switched off just before 'internal sunset' (23:30). An hour later an aeration pump kicks in to maintain oxygen levels at night and that switches off an hour before 'internal dawn' (11:30). Lighting is achieved using Juwel's excellent Helialux system using two units and their network attached controller. This allows you to programme / control the wavelength of light during the day to simulate dawn / dusk as well as cloud cover and you can even simulate the changing light that accompanies a storm (as in the Amazon, there is a tropical storm most afternoons at 15:00 in the tank!). And being network controlled I can even access it remotely to compensate for the growth of floating plants obscuring the light while we're away (I set a network camera up to 'watch' the tank).

Anyway, this post seems to have run-on somewhat, but to reiterate, I do have some fish!

Hallie (born Harold)
Purebred Bombay... big boy weighing in over 16 pounds.

Tricky little fellas to photograph using a compact camera, but this is one of the juveniles eying up some prey on the moss. As I mentioned above, it is only about 8 mm long at the moment and this one is a bit darker than the other and both have yet to develop their adult tail and fin shapes.

Thanks, Jules... the Bombay became a cat breed in the mid seventies and was derived from sable Burmese and black American short hair cats.

They received their name because of a resemblance to the black panthers that live in and around Bombay, India. There gait is much more like that of a panther and Hallie doesn't meow. Instead they have a unique call and tend to be quite vocal, even conversational! Despite being very muscular and athletic Hallie is extremely gentle and polite.

He is the friendliest animal I've ever encountered and knows no fear when meeting new houseguests for the first time. They are always surprised, to say the least, when this 16 pound mini panther winds up plopping himself onto their laps shortly after making acquaintance.

Listening to music is one of Hallie's favorite pastimes... A very special addition to our family indeed.

The Windsor chair is oak and one of six that go around their matching dining room table. The set has been in the family for several decades.