Full Fish Ahead: Part 4

It’s time to check in with Avalus to see what’s up in the new aquarium.

Part 4 – Technically Challenged

You could see it in the last part of Full Fish ahead: I modified the filter inlet tubing. Today I want to talk about what I did and why.

A word of warning: When playing around with water, make sure you have no non-water safe electrical McGuffins running in the splash zone and test, extensively, if your seals are really waterproof (for example overnight in a box).

As you can see, I have a darker background. It is an old towel and will be replaced later on by paper. ©Avalus, all rights reserved

A darker background helps to calm shyer fish and lets their colours stand out. I also cut some of the plants in the middle (Didiplis diandra) to give the other plants between space and light (Hygrophilia Araguaia and cryptocoryne wenditii).

The filter comes with 16 mm hose and an inlet piece that fits the hose. The Problem with this is threefold. One, the Inlet has few large openings, small fish and especially shrimp will get sucked in the filter. It also congests really quickly. Then, just behind the inlet, the water flow is choked and because of the small diameter there is much resistance from the walls, resulting in higher strain in the pump. Also the hose really quickly plugs up from particles sticking to the walls and bacterial mats that will grow.

©Avalus, all rights reserved

So I decided to use 22 mm hose for the water flow from the tank to the filter. The nice thing is that I can just heat the larger tube with hair dryer, slide the big tube over the small one and get a tight seal. The black thing is a bender that I bought to prevent kinks.

Inflow on the right. The smaller diameter hose ends just over the “9” of the printed number. ©Avalus, all rights reserved

The next piece is a bit of polyethylene tubing. It is sanitary equipment and as such food safe. I cut it to the appropriate length and then drilled many, many 2 mm holes in it. And then some more, after testing the response of the pump. This configuration leads to a slow flow speed over the surface and so prevents weak swimmers (fish fry, shrimplets) from being sucked in. The large surface prevents clogging. The tube and the hose don’t fit perfectly, so I improvised a seal with a household rubber band. I will re-seal it, when I find appropriate, food safe O-rings. As the last step, I glued a piece of bamboo I had left in the bottom of the tube to seal it. I drilled a tiny hole in the bamboo plug so no air would be trapped and glued a coil of 1 mm V2A stainless steel wire inside (useful stuff! Still have it back from the time I repaired chainmail…). The extra weight should keep the whole tube pointed down in the tank and the bamboo is a convenient anchor.

©Avalus, all rights reserved

The outflow (filter to tank) has clean water without many particles and thus the 16 mm hose is fine. I am still playing around with the pieces of tubing that came with the filter to get a water current in the tank that I like. To lower the velocity of the water flowing in the tank I constructed a flowbrake by widening the diameter of the hose.

Finished setup, outflow with flowbreak in the front, inflow in the back. The bender is secured to the hose by more rubber bands. ©Avalus, all rights reserved

From the side you can see the filament algae evenly distributed over the whole surface. ©Avalus, all rights reserved


No rant, but more pretty pictures.

Also last week I wrote about the shrimps’ reckless abandon, this time I have photographic proof as I cleaned the shrimp tank. I held the animal under the water all the time, but that’s hard to see.

The strategic genius says: Use the weight of your foe against themselves. ©Avalus, all rights reserved

And nibble at the hand that feeds you, while you’re at it. ©Avalus, all rights reserved

A baby pearl shrimp (Neocaridinia palmata). The red markings will vanish in the next moult, sadly. ©Avalus, all rights reserved


The new tank got some new inhabitants! There are a dozen colourful new shrimps (Neocaridia davidi, red and blue), nine Khuli loaches (Pangio kuhlio) and four honey gourami (Trichogaster chuna).

Khuli loach, ramshorn snail and a platy, sharing a food tablet. ©Avalus, all rights reserved

Khuli loaches cuddling between the glass pane and the thermometer. They are still in stress decolourisation from travel. They are about 6 cm long. ©Avalus, all rights reserved

Here you can just make out the feelers under their snout. ©Avalus, all rights reserved

The tropical loaches are interesting fishes as they do not have scales. Instead they have a tough flexible skin, but that makes them vulnerable to injury by scratches. These specific ones have an unusual snake like body and they like to burrow in fine soil like sand. In nature, that’s where they find their food of worms and insect larva, in the tank they seem to do it just for the fun of it. They are said to be shy but without larger fishes in my tank, they are curious and active. And they like to snuggle as seen above. Either in groups of their own or with the similarly social corydoras catfishes. They also like to jam themselves into any nook and cranny they can find. This is another reason why I build my own outlet to the filter.

Honey gourami pair; my camera has difficulties to get focus and colours right. Male in the centre, female behind the circle above. ©Avalus, all rights reserved

The honey gourami are just plain beautiful with a deep yellow to brown colouration and an accentuating black strip under the chin for the males, while the females have a brown stripe along their side and are more camouflaged. They can be pretty territorial when they feel like breeding and are rather shy otherwise, so a highly planted tank with sight blockers, nooks and crannies to hide in helps to keep the peace. They love the depth of the wood piece and swim through the openings.


Link to Full Fish Ahead: Part 3


  1. lochaber says

    nice, thanks for the update. I love kuhli loaches, they are adorable little weirdos.

    I’ve usually tried to use foam prefilters for the filter uptake. I could usually find them in pet shops, but have also made them by just cutting a slit in a piece of foam and sliding it over the tube.

    My last setup, I did a small mattenfilter-type thing and had the filter uptake behind that, and it seemed to work really well, I’ll probably do a similar thing next time I set up a tank.

    I’m really fond of painting the back glass on the tank. When I had a place with a yard, I would just use black spraypaint. The past couple tanks, I’ve been in small apartments, so I did latex paint, it took a few more layers, but worked really well.

  2. avalus says

    Thank you lochhaber. I tried painting, but I like something I can replace easily.

    @Marcus: No, it is a LG K4 cellphone and for close up shots I hold a cheap clockmakers lense in front of the camera. That means, I can only get closeups of things that are around 1-2 cm away from the glass panes. The baby pearl-shrimp was photographed that way, you can see the black eyepiece of the lense (I photographed it here (https://freethoughtblogs.com/affinity/2019/03/07/a-tiny-snail/)).
    Somethime in the future, I think I will invest in a real camera with usable zoom and autofocus that does not leave me swearing half the time.
    Dunking a GoPro sounds intriguing! :D But I think most of my fish would flee. In fact, they even react to the the cellphone, I guess they think the black block is a threat. The gouramis needed a lot of bribes (snacks of tiny worms) to stay long enough in the light to be photographed.

  3. rq says

    The loaches and shrimp are adorable!
    I admit, the technical aspects are well outside my field of knowledge, but I think it’s something I have to get used to, as Middle Child might soon be a lizard-keeper, and this also involves a lot of research into caring for pets that are well outside my field of knowledge…

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