In Fish Cycling (Again)

[KirkyArcher]

I was just wondering about peoples thoughts on the use of very hardy wild fish to cycle a tank, here in the UK Minnows and especially 3 spined Sticklebacks can survive in some pretty inhospitable conditions is there a biological reason why some fish can survive in such harsh conditions and others can't.

 

[fluttermoth]

There are multiple reasons why this is a very poor idea.
 
For a start, minnows (and sticklebacks) are very sensitive to heat and the minnows need very high levels of oxygen. They are no more 'hardy' when it comes to ammonia or nitrate than any other fish, and considerably less so than tank bred fishes. The waters they live in might look filthy and poor, but in terms of toxins, they're generally quite clean; zero ammonia and nitrite at all times and very low nitrate, if any at all.
 
Cycles go faster at higher temperatures, so you'd be along time cycling in the cool waters that hose fish prefer.
 
Wild fish could carry pathogens or parasite that they are immune to, but that aquarium fish would not be. Anything in your tank, like decor or plants, could also infect the wild fish in the same way, so you would never be able to release them back into the wild, you'd have to keep them permanently.
 
It's also illegal in many places to catch wild fish; although I doubt you'd get into trouble over a few minnows, but that's hardly the point.
 
Anyway, the reason fishless cycles were 'invented' was to save any fish from being harmed; why would you want to inflict potentially lethal amounts of ammonia and nitrite  on any fish, even wild caught minnows?
 
As to why some fish are hardier than others, it's all down to where they evolved to live. If there are rivers or lakes that experience ammonia, then I'm sure some fish would evolve the ability to cope with higher levels.

 

[Noahsfish]

The only fish I've ever used to cycle a tank before were harlequin rasboras, and that was my very first tank. I surprisingly had no losses even though at th time I wasn't aware I should be doing water changes daily..

 

[KirkyArcher]

cheers for the replies just curious. 

 

[fluttermoth]

You're welcome
 
It's good to have discussions about these things!

 

[levahe]

If a person was intending on starting a planted tank from scratch, they could then do a 'silent cycle' which is basically a heavily planted aquarium and a low bioload.
Most people don't start with plants though so I don't think its going to take off any time soon lol!

 

[eaglesaquarium]

Its taken off, amongst the 'planted' tank types.  There's just less of them than other fishkeepers.

 

[Noahsfish]

I think that's a more viable option for more serious fish keepers who have multiple tanks...most people starting off don't just jump into heavily planted tanks.

 

[FreshwaterAfishianado]

How does this "silent cycle" work? Is the idea that the plants absorb the ammonia and nitrite to keep it at acceptable levels? Just curious as I've never heard of using plants to cycle a tank, would this take longer to establish a biofilter because the plants and bacteria are competing over the same nutrients?

 

[TwoTankAmin]

Plants eat ammonia. Therefore the only ammonia available for bacteria is what the plants do not consume. The more plants and the faster growing they are, the more ammonia they consume.
 
The need to cycle is therefore minimal. The only way to have nitrite is to have ammonia converted to nitrite by the bacteria. But there are only a few bacteria for ammonia since the plants are using most of it, so nitrite never gets high either.
 
You plant up a tank well, give it some time to establish (put out new roots) and start adding fish. You should never see ammonia or nitrite. You can not add fish to stock fully, but you can go way faster than with a fish in cycle. The more plants the more fish to start. If you are super anxious you can even throw in a few fish right away, just not ones that root around in the substrate or you will have floating plants.