Ever since mid 1980's, each year starting from spring till the mid of  fall (depending if the weather conditions are reasonable enough, of course), I put a certain amount of fish (mainly livebearers) in PE tanks and glass cubes.  I don't use any filtration of what so ever and an air pump will only be activated when it becomes extremely hot outside.

Using pond plants instead of the regular aquarium plants creates a natural habitat to the fish. Even in free nature these fish are dealing with big temperature ranges. During the day hot and during the evening and night significant colder. For the mistake which a lot of people make is to label a lot of fish as tropical while in fact a lot of the aquarium fish should be labeled as subtropical. 

The results of keeping them outside are :

* Fish are much stronger

* Fish colouration is much more intense

* Fish are becoming much larger

* A higher reproduction ratio

If you would  get the chance to do the same.. I'd advise you to do so... And it's also fun to watch the fish from the top instead from the side!

Well, there are many ways to keep your aquarium fish outdoors. I use tubs, glass cubes, normal fishtanks and inflatable swimming pools. As long as it works, I don't mind what kind of subject to use as an accommodation for my fish.

Left: Me feeding my fish outdoors. In general you don't have to feed fish that are kept outdoors unless there's a lid. For open fish environments attract insects (which lay eggs), algae is growing in it and more natural nutrients that your fish need. In fact it's a self sufficient environment to the fish. And it's important that the wind will catch some surface of the tub, tank or whatever you'd like to use to house your fish.

Like I've already mentioned, an inflatable paddle pool can be used as well. Just be sure where you'll place it (goes for every kind of outdoor fish environment, btw). It's very important to choose a spot in the sun, shadow or even half shadow depending on the kind of fish you'd like to keep. Every species has got its own needs. You can even choose to keep the tubs or tanks above the ground or dig them partially in (to create two levels of temperature). Certain species prefer to choose between temperatures during the 24 hours that the clock shows. Think of a number of members of the Xiphophorus and goodeid family.

Above: An inflatable paddle pool used as a pond filled with plants and some stone hiding spots (photo left). Me enjoying my livebearer pond in the backyard (photo right).

Above: A video of a mix of livebearers in a paddle pool in the backyard.

Observing fish from the top is something I really like to do. Wether that´s in one of my tubs, swimming pool or another kind of housing. You don´t always have to scoop fish and put them in a small container or something similar. But for sure I do check them like that as well. Further on in this section you´ll read about it.
Below: Overhere some photos of mostly swordtails in the swimming pool in the backyard.

Below:: Overhere some guppies in an outdoor tub.

Below: An adult Xeonotoca doadrioi is coming to the surface of an outdoor tub for food (photo left). Some white cloud mountain minnows are reaching the surface of an outdoor tub for food (photo right).

But also fishtanks are used during the outdoor season. Look at the photos below. This tank is situated on the balcony. While the backyard is on the south side of the house and during summer the heat of the sun can be very intense during daytime; the trumpet vine that´s present, covers the fishtank. It gives the fishtank the shade it needs and protects it from the intense heat. A very good solution for the fish kept in there.

Above: Some white cloud mountain minnows (photo#1).
Above: Least killifish (Heterandria formosa ♀ (photo#2)

Above: This tank on the balcony contains Heterandria formosa, Xiphophorus milleri, Blue rio guppies (breeder: Kenjiro Tanaka) and White cloud mountain minnows.


Checking out on my fish

From time to time I do check out on my fish. Not that it's necessary. For in general, I don't really have to worry about them. In their natural created biotopes in the outdoor tanks, they have a splendid life! Diseases are less common in comparison to indoor tanks.

Basically, it's more my curiosity which triggers me to check out on them... It's quite fun and interesting to watch how these fish are developing . And how they survive outside within our Dutch climate. The growth rate is much higher than in the indoor tanks.


Testing the water conditions of the tanks

Just like the indoor tanks, the waterparameters of the outdoor tanks will be checked by me as well on a regular bases. Like I've already mentioned, I don't filtrate mechanically for it's a complete natural biological situation in the outdoor tanks.

In general, the parameters are just fine but it's just a secure check. Variable influences like e.g., wind,  rainfall, sun, heat, etc... can create an unbalanced situation within the parameter household. Fortunately, those ain't bothering my outdoor tanks.


Hatching my own daphnia

In order to keep the costs as low as possible but without any loss of the quality of livefood, I'm hatching my own daphnia (Cladocera daphnia) in two outdoor tanks.

I'm really convinced that livefood is way more nutritious than dried flake food or granulate and therefore I always give all my fish livefood at least once a week.  The outdoor fish already have the facility to feed themselves with livefood becoz' of the natural habitat they're in. For nature looks much more better after them than we could ever do ourselves.

In both tanks some crayfish are living in them during two seasons a year. As long as the temperature won't get below 5°C, they're doing just fine.


During fall

So, I usually get my fish out of my outdoor tanks somewhere during fall to let them survive inside. In fall (2012) I got the last ones out mid October. All the other fish were already taken inside starting from the beginning of October.

Overhere I was getting the Ameca splendens and one koi out of the black PE tank and put them in a bucket. Then I got the water out of the PE tank until a low level was still in there.

The tanks on the balcony had a water temperature of 8°C and the tank in the backyard had 10°C water temperature at mid day in mid October. So, at night it was a lot colder for we had freezing nights back then. But all fish were still happy swimmers and the same goes for the crayfish I had outside.

The water was really cold to my hands. As the pic on the right shows, it was 10°C of water temperature. But no harm has been done to the fish. Even the endemic habitat of Ameca splendens knows cold seasons. These fish are so hardy that in fact these fish are the perfect solution to lazy fish keepers.

One of the last juvenile Ameca splendens were taken out of the tank by hand. They can survive for a little while out of the water. If you'll get them out as shown, they tend to fake being dead. Just a surviving strategy. But once you put them into water, they'll swim away as if nothing has happened.

So, after that was done I started with the last tanks on the balcony where I still had crayfish outside.

I myself take mostly my fish and crayfish out of the water by hand. In a way it's way better for the livestock than using a fishnet. And it's aso fun to catch them by hand to be honest...

These crayfish did well with these weather conditions. The water temperature in these tanks was 8°C during the day. No loss of fish in general outside. I also got some cherry shrimps and japonica shrimps from outside that particular month.

All livestock from outside were kept in buckets for the night and by the next morning the temperature  of all buckets were equal to all the other tanks inside. And it was about time to put all the livestock from outside in their new tanks.


Harvesting guppies in November 2023. The water temperature durng the day was 12°C and the guppies were still much alive and dropped fry. This proves again how hardy guppies can be. It seemed that even their metabolism didn't go low at this rate for they still ate well.


I'm always looking forward to the next spring period to start all over again....