Can adding a too large bio load crash your cycle?

[AuroraDawn]

I was told by a fish store guy that when you cycle a tank and then have smaller fish or less fish, a smaller bio load; sometimes if you add a bunch more fish or one or two big fish, the bio load increases over the amount that the amount of beneficial bacteria can process fast enough to keep the tank fish-safe for levels of ammonia, nitrite and nitrate. Is this true? How do you avoid this?

I have been cycling two 35 gallons, both have Seachem tidal hobs that come with foam and ceramic media that you put in. I have some plants in both and gravel. No fish. I have been dosing with beneficial bacteria: Aqueon Pure live beneficial bacteria and enzymes, API Quick Start and also Start Smart Complete Multi-purpose. I have also been ghost feeding with Fluval flakes. I try to ghost feed daily, sometimes I forget. Am I feeding the beneficial bacteria enough or am I just wasting a lot of it?

My concern is this: What if the beneficial bacteria that lives and grows is only proportional to the amount of nitrate created from the flakes I am putting in? If the tank appears cycled but is based upon the flake input, if I put in 6 juvie freshwater angelfish... is it gonna crash and make my fish sick or worse? Should I be dosing the tanks with something else, and if so, what and how much?

Thanks so much in advance to all who care to share any wisdom and experience on this!

 

[Noroomforshoe]

"I was told by a fish store guy that when you cycle a tank and then have smaller fish or less fish, a smaller bio load; sometimes if you add a bunch more fish or one or two big fish, the bio load increases over the amount that the amount of beneficial bacteria can process fast enough to keep the tank fish-safe for levels of ammonia, nitrite and nitrate. Is this true? How do you avoid this?"

That is my understanding from what I have read and heard. You can avoid this by adding only a few fish at a time. then testing the next 2-3 days, and if you still have zero ammonia and zero nitrite and 10-20 nitrat, add a few more fish, and repeat untill you finish adding all of one species of fish, Ideally wait another week or more to start adding another species,

Or you can use a lot of very dirty filter media and you might be able to add fish faster, but it is safer to start a new tank slow no matter wat, I know that some fish are going to be stressed when they are not in a school. I know that buying fish online usually means buying a lot of fish at one to make the shipping cost worth while.

 

[kallililly1973]

That’s my same understanding as well. I don’t think it’ll crash your cycle but you may experience a “mini cycle” where you might get ammonia and some cloudy water till the beneficial bacteria catches up to the bioload.

 

[Fishfur]

I was told by a fish store guy that when you cycle a tank and then have smaller fish or less fish, a smaller bio load; sometimes if you add a bunch more fish or one or two big fish, the bio load increases over the amount that the amount of beneficial bacteria can process fast enough to keep the tank fish-safe for levels of ammonia, nitrite and nitrate. Is this true? How do you avoid this?

I have been cycling two 35 gallons, both have Seachem tidal hobs that come with foam and ceramic media that you put in. I have some plants in both and gravel. No fish. I have been dosing with beneficial bacteria: Aqueon Pure live beneficial bacteria and enzymes, API Quick Start and also Start Smart Complete Multi-purpose. I have also been ghost feeding with Fluval flakes. I try to ghost feed daily, sometimes I forget. Am I feeding the beneficial bacteria enough or am I just wasting a lot of it?

My concern is this: What if the beneficial bacteria that lives and grows is only proportional to the amount of nitrate created from the flakes I am putting in? If the tank appears cycled but is based upon the flake input, if I put in 6 juvie freshwater angelfish... is it gonna crash and make my fish sick or worse? Should I be dosing the tanks with something else, and if so, what and how much?

Thanks so much in advance to all who care to share any wisdom and experience on this!

It can’t crash your cycle - a crash involves loss of nitrifiers and adding too many fish at once doesn’t kill nitrifiers.

What it does is overwhelm their capacity to oxidize all the additional ammonia, but this is only temporary and the nitrifiers will catch up.

They catch up by multiplying in numbers. They only divide roughly once a day so it may take awhile before they catch up.

The number of nitrifiers is always just high enough to oxidize the ammonia that’s present & no more. You could have a filter as big as the tank itself, but it will be able to oxidize only as much ammonia as it is used to. Add more bioload and it’ll have to catch up too.

The capacity for oxidizing ammonia can be increased only by increasing the ammonia supply first. But then it will take some time for the nitrifiers to reproduce sufficient numbers to manage the increase.

If you add more load than the nitrifiers are able to oxidize completely, you would have to do extra water changes to make sure nitrite never rises above .25ppm until the nitrifiers catch up.

I say nitrite rather than ammonia because nitrite is the greater danger and keeping it under control also takes care of the ammonia.

 

[AuroraDawn]

I have 6 juvie angels waiting for a tank to be cycled and they eat a lot since they are still growing.

I also have 12 baby angels that eat a lot but are quite small.

could I try ghost feeding more food to produce more ammonia so the cycle is used to more bioload?

 

[Fishfur]

I have 6 juvie angels waiting for a tank to be cycled and they eat a lot since they are still growing.

I also have 12 baby angels that eat a lot but are quite small.

could I try ghost feeding more food to produce more ammonia so the cycle is used to more bioload?

Sure - anything that increases the amount of ammonia will increase the size of the nitrifier colonies.

Might try using shreds of shrimp or fish - since they’re mostly protein & no carbs, they’ll produce more ammonia gram for gram than fish flakes.

 

[A201]

The size of the juvenile Angels will also make a difference on how many of them to add.

A lot of waste difference between a dime sized Angel and a quarter sized one.


.

 

[AuroraDawn]

Sure - anything that increases the amount of ammonia will increase the size of the nitrifier colonies.

Might try using shreds of shrimp or fish - since they’re mostly protein & no carbs, they’ll produce more ammonia gram for gram than fish flakes.

I believe they are mostly protein as they are made from some kind of ant larvae.

Would some frozen brine shrimp be better?

The size of the juvenile Angels will also make a difference on how many of them to add.

A lot of waste difference between a dime sized Angel and a quarter sized one.


.

The juvies are all bigger than a quarter, 6 of them.

The babies range from dime to a tad bigger than a nickle, 12 of them.

 

[bgarthe]

I may be missing something, but if you have a current tank with the 6 Angels in it and you have put beneficial bacteria into your waiting 35g, then take the filter from the tank they’re in now and either put it on your 35g or squeeze out the media from it into your new tank filter. Then add a few fish at a time or a week. The same would work with the tank currently holding the 12 youngsters. Seeded fish in cycling works fine. If your bb numbers are higher than the fish bio load, they’ll taper off a bit until you increase the bio load. If your bb numbers are lower than the fish bio load, then they’ll increase accordingly. Critical……Adding small numbers of fish at a time really helps to make the bb ebbs and flows go smoothly.

And lastly, your bacteria levels are not affected by nitrate produced by the flakes, but ammonia. Nitrate is a product of a cycle….ammonia to nitrite and then nitrite to nitrate.

 

[FishDin]

Several good suggestions above.

The bottled bacteria are supposed to allow you to add fish from the start. Why haven't you done that? If you are trying to grow your biofilter, but don't want to add fish, you could also start adding ammonia instead of food, which makes it easier to reach the levels usually achieved with fishless cycling (which is what you are doing). It also makes it easier to know how your cycling is progressing.

When ghost feeding you should feed at least as much as you are or will be feeding the fish.

The problem with bottled bacteria is that they often don't work. It's hard to know if it's working when ghost feeding. Adding fish or ammonia allows you to track the process easier and intervene when needed.

And as pointed out by bgarthe, there is no need to cycle from scratch if you have a cycled tank you can borrow filter media from.

 

[Fishfur]

I believe they are mostly protein as they are made from some kind of ant larvae.

Would some frozen brine shrimp be better?


The juvies are all bigger than a quarter, 6 of them.

The babies range from dime to a tad bigger than a nickle, 12 of them.

Just so you’ll know, fish food flakes as a group contain a lot of complex carbohydrates. They must, as it is the carbohydrates that make manufacturing flakes possible.

The very best of them quality wise MIGHT be as low as 15% complex carbs but a lot are close to or over 50% complex carbs. The worst of them might be closer to 70% or even more. I’ve seen at least one brand that had wheat flour as its first ingredient - very sad..

Since this particular percentage is never listed on the label, there is no way to know if the flakes you use are on the high, middle or low side of carb content.

Fish and meats contain no carbs to speak of and non complex carbs. Y

 

[VSA]

It’s already been mentioned that describing it as a crash is probably not accurate. But there is a broader point that it depends really. Your average fishkeeper adding 4ppm ammonia to cycle their tank is going to need a lot of neon tetras to exceed the bioload the tank is already set up for.

 

[DaveKS]

Sure - anything that increases the amount of ammonia will increase the size of the nitrifier colonies.

Might try using shreds of shrimp or fish - since they’re mostly protein & no carbs, they’ll produce more ammonia gram for gram than fish flakes.

True, but secret is to bring it up slowly, in small tanks most shreds of shrimp etc will overwhelm system. Slower decay of some other pre-processed food (bug bites/other processed food) is much preferred.

What you describe I would actually do in 40g breeder, but not in a 5g tank.

 

[GlennO]

When adding a number of new fish or large fish I always go easy at feeding time for the first week or so.

 

[DaveKS]

When adding a number of new fish or large fish I always go easy at feeding time for the first week or so.

Hand curated target feeding. Feed them well but don’t let anything go to waste. Small amounts of fish poop added to system. System will catch up being as waste is semi-processed fish waste.

 

[MagnifcentBett]

I did wonde about fish not. havin a comfortable number to school.

 

[GlennO]

I did wonde about fish not. havin a comfortable number to school.

Shouldn't be an issue in the short term as long as they are not too exposed and have plants or other things to shelter amongst.