Your fish houses: Mats Petersson


A single room dedicated to fish is not enough for catfish fanatic Mats Petersson. His hobby has consumed not only his mind and body, but much of his home too. Nathan Hill steps inside four walls that embrace a veritable empire of fish - a fish house in the truest sense of the word!

Fishkeeping is a diverse hobby. You can just dip in a toe and take on a single tank, or you can take the plunge and immerse yourself totally in life aquatic.

This latter approach has been adopted by Mats Petersson — a person deciding to go all out, buying a one-way ticket to the hobby and never looking back.

He’s widely recognised in fishkeeping circles and known to many simply as Mats P.  Wherever conversations regarding catfish take place he’s sure to appear, though his knowledge isn’t restricted to those fish that live on the bottom.

Some people opt for a fish house, a steaming, insulated shed of tanks at the foot of the garden, but Mats has done something similar with his actual house and tanks swing and sag from every angle.

To walk in feels as though you’re entering a shop and it takes some time to find your bearings and grasp that you’re actually in someone’s home instead.

Mats has certainly earned his stripes for the time served in the hobby. After 35 years of keeping and breeding, he has learned much along the way.

He reflects that if he’d known then what he knows know, he’d have done things differently.

Either way, that first tank, a 45 l/9.9 gal all-glass holding a brace of guppies, set things in motion for the larger enterprises he undertakes today.

Mats became more serious about fishkeeping in late 2004, having purchased a Juwel Rio 400 which still runs to this day. In this he kept Satanoperca leucosticta alongside other more community fish. They went through the motions of breeding several times, though never officially produced any fry.

From there, the bug really bit. Even some of the fish from that original Rio are seen today in the form of very large and belligerent Brochis catfish.

Looking around Mats’ selection of 14 tanks, it’s initially hard to find a theme. There are cichlids here, namely a selection of large, bold and colourful eartheaters (pictured above is Geophagus neambi).

There are barbs, and there are characins. There are many catfish. The natural light filtering in to this open and bright room seems to do wonders for fish colours, and everything looks that little bit more vibrant than I tend to see elsewhere.

Interviewing the man, it’s obvious that his strongest love is for the silurids. Anything whiskered is welcome and every tank has some kind of cat lurking within.

Top of the Mats’ cats are the loricariids and plecs are a favourite.

Citing a lack of any interesting marine catfish, Mat says this is one reason he’s never had the desire to dabble with any marine fish.

In fact, he had his first breeding success with catfish, producing clutches of Ancistrus fry. He’s clearly got a feel, as even several years on there are tens upon tens of these fish from frequent breeding exploits scattered throughout several aquaria.

The frames on which all the tanks sit are of Mats’ own construction. The wooden scaffold was built from scratch, taking a day and a half to put together, before he could move items over from his previous home. The main rack, holding seven assorted tanks, cost a little over £200 to assemble, as a guide to those thinking of such a task themselves.

The tanks vary from the largest, original Rio 400 at 151cm/5’ long, down to some 45 x 30 x 38cm/18 x 12 x 15” aquaria. Mats stacks these latter ones end on, allowing for maximum volume over narrowest rack width. Most are located in the front room, but a quick jaunt next door into the kitchen reveals even more stacked there, smaller and more focused on individual breeding efforts.

In all, he has some 2,500 l/550 gal of aquarium water scattered around the ground floor.

Filter medley
Even the laundry room is utilised. Here, more racking houses three 114 l/25 gal water tanks fed by an RO unit, giving Mats all the supplies he needs to carry out frequent maintenance.

his tanks are a medley of canister filters, both internal and external. Mats favours Eheim units, especially the classic 2217 and 2215 models. There’s a larger 2080 unit too, which was found by a friend investigating a rubbish tip. A quick makeover and the filter was as good as new and ready for use.

He opts for many filters of the same types, in part for security reasons. With so many matching units it’s easy to butcher pieces from each other and it gives him plenty of back-up options if ever one of them fails.

Koralia flow plumps are utilised in some of Mats’ tanks to create extra water movement.

Mats locates his hardware from multiple sources, buying bulk where possible to keep costs down. He is vocal about providing trade for local businesses, preferring to buy from brick and mortar stores than the online world. However, with astute shopping and some purchasing from auctions, Mats can maintain his hobby without empyting his wallet.

The same mentality towards buying prevails with livestock. Mats doesn’t like to buy fish online, preferring to determine sexes for himself, as well as oversee the quality of the fish he’s taking on board. He’s not against the carriage of fish, acknowledging the benefits of delivery for people who might not be able to travel or are too far from suppliers of rarer species, but it’s not for him.

He’s also prepared to travel for new specimens and is a regular face on field trips to faraway sites, taking journeys all over the country for prospective purchases. That said, he’s not a fan of investing in ultra-expensive fish and cannot be motivated to spend £600-700 on a couple of cats for breeding.

The selection he has is pretty much testimony to the fact that you can have an exciting range of livestock without having to pay the earth for it.

He likes to plan tanks for fish in advance, rather than diving in, buying something and trying to accommodate it later. As it is, there’s nothing under his roof that could potentially present problems of outgrowing or becoming otherwise hard to cater for, so he’s true to his own ethic.

Mats tells me that he’s more fishkeeper than aquascaper. Plants feature large in the displays, but their roles are designed to be functional rather than visual. Duckweed plays a part in providing surface cover in some tanks and sprigs of other greenery — typically hardy pieces like ferns — provide cover and grazing opportunities elsewhere.

Enhancing algae
Hints of algae are here but none that are problematic. He’s dabbled with Easycarbo before, and with limited effect, but the tufts visible aren’t offensive. If anything, they enhance the natural feel of the aquaria. It’s interesting that the cats in some tanks have not only controlled this growth but have left décor stripped bare, resulting in sawdust films on substrates.

Décor is a mixture of wood types and Mats likes to experiment with various kinds. There’s shop-bought Mopani, and birch, willow, cherry and apple scattered about. Some bits have been purchased, others picked up on travels.

How much work does such a set-up take? How much does it all cost? Mats hasn’t noticed an increase in fuel costs based on what he has, but is more concerned about the potential for increased water bills. RO water, being high wastage, tends to use much more water than it provides.

Bulk buying on foods keeps spending down and he prepares many frozen foods himself. Plenty of green foods are used too.

A cursory glance of the tanks shows a number of spoons, which baffled me until Mats explained that they are used to skewer pieces of cucumber in place, weighing them down for grazing cats.

Medication costs are low, as Mats only treats when there’s an actual problem evident, opting to eschew the palliative approach of medicine in fishkeeping.

Water changes take place over three-weekly sessions. The trick, as Mats is happy to reveal, is to use a long length of hosing for water extraction, taking it straight outside, cutting out all that lugging and other backbreaking labour.

His only restriction when changing is the refill rate, assisted by an inline pond pump on the hoses feeding from the RO vats.

Right conditions
Minerals are added directly to the tanks and a TDS meter ascertains mineral levels. For the best part, tanks are kept at just over 100ppm, though he will lower this for breeding purposes.

I asked Mats why he opted to have a fish house, but I was quickly corrected. What he has is a fish room — and his reasoning was simple: more tanks equals more fish varieties and he enjoys seeing the numerous types in his care.

For him it’s all about keeping fish in the right conditions. He doesn’t claim to be a biotope purist, preferring to work to water compatibility. Looking at the quality of fish he has, I have to say he’s certainly on the right track…

What’s in all the tanks...
It was a matter of my relentless curiosity to discover what Mats  is keeping. Being well aware of his reputation, I was desperate to list what was on show. Here’s what I found there— and I wasn’t disappointed:

Cyprinids
African banded barb (Barbus fasciolatus),
Clown barb (‘Puntius’ everetti),
Snakeskin barb (‘Puntius’ rhomboocellatus),
Dadio (Laubuca dadiburjori).

Catfish
Panaquolus sp. L204,
Asian bumblebee catfish (Pseudomystus siamensis),
Dull-eyed royal plec (Panaque sp. L191),
Spotted orange seam plec (Hemiancistrus guahiborum),
Corydoras panda,
Corydoras metae,
Dwarf giraffe catfish (Anaspidoglanis macrostoma),
Peckoltia sp. L147
Mystus mysticetus,
South American bumblebee catfish (Microglanis iheringi),
Black pygmy driftwood catfish (Tatia aulopygia),
Corydoras virginiae,
Ancistrus sp. L338,
Synodontis contracta,

Loricaria similis (pictured above)
Unknown Hypancistrus bought as L411,
Woodcat (Tatia gyrina),
Ancistrus cf. cirrhosis,
Brochis splendens,
Pseudacanthicus sp. L065,
Gold marbled ancistrus (Ancistrus claro),
Corydoras sodalis,
Corydoras sterbai,
Megalechis thoracatum,
Corydoras robinae,
Synodontis brichardi,
Synodontis decora,
Leporacanthicus triactis,
Synodontis flavitaeniata.

Characins
Nannostomus eques,
False neon tetra (Paracheirodon simulans),
Nannostomus beckfordi,
Nannostomus minimus,
Nannostomus marginatus,
Colombian blue tetra (Hyphessobrycon colombianus),
Congo tetra (Phenacogrammus interruptus),
Diamond tetra (Monekhausia pittieri),
Nannostomus trifasciatus,
Lemon tetra (Hyphessobrycon pulchripinnis),
Bloodfin tetra (Aphyocharax anisitsi).

Cichlids
Geophagus parnaibae,
Geophagus sp. ‘Tapajos red’,
Geophagus neambi.

There may be even more I’ve missed and Mats may have picked up a few extras since I visited, but, whichever way you look at it, that’s quite a hoard!

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