How long before I add my fish?

[Ponera]

Hey all,

After some crazy moves I am finally setting up my 45 gallon tank again. The plan is to have a single half-grown captive bred male senegal bichir and maybe some top dwelling friend, depending on what the bichir is like. I set up the tank last night, added some cycle and dumped in like 10 fat head minnows to get it going. The minnows are all dying off, but given the condition of them in the first place I am not really that surprised.

How long should I wait before adding that single fish to the tank? The internet has opinions ranging from 24 hours to 8 weeks.

 

[Rocksor]

Get an API freshwater test kit and study how to do a fish in cycle. There is no way to cycle a tank from start in 24 hours with just fish (no bacteria in a bottle and now seeded media). The average cycle time with fish is roughly 8 weeks.

 

[Ponera]

Okay but doing fish-in cycle requires a fish. So do I toss in the bichir this week or wait the 8? I added bacteria in a bottle last night actually.

 

[Rocksor]

Okay but doing fish-in cycle requires a fish. So do I toss in the bichir this week or wait the 8? I added bacteria in a bottle last night actually.

You can do a fish in cycle with the fathead minnows, and you still need an API liquid test kit to determine when your tank is cycled, even with the bacteria in a bottle.

 

[Ponera]

Yep, I have a test kit already! So if I toss a bichir in today to actually provide the needed ammonia and test the water every other day, it should be okay, right? The fat heads are dying fast but they are super scrawny underfed feeders from a local shop...so their life expectancy is generally "dies when moved" anyways.

Apparently the store got in some feeder guppies, they tend to be better shape than the fatheads. Maybe I should toss in 15 of those and let them sort out instead of a bichir for now?

 

[Rocksor]

Yep, I have a test kit already! So if I toss a bichir in today to actually provide the needed ammonia and test the water every other day, it should be okay, right? The fat heads are dying fast but they are super scrawny underfed feeders from a local shop...so their life expectancy is generally "dies when moved" anyways.

Apparently the store got in some feeder guppies, they tend to be better shape than the fatheads. Maybe I should toss in 15 of those and let them sort out instead of a bichir for now?

I wouldn't get the bichir now. If you don't think the fatheads will survive, and after they are dead, you're better off doing a fishless cycle with pure ammonia (which does not bubble when shaken). Dose up to 2ppm ammonia.

 

[Ponera]

The store has mature filter media I can buy. They claim that plus the bacteria I already dosed it with should do the trick. I have a filter rated for a 70 gallon on this 45, so it'll blast the water through that media hella fast. Thoughts?

edit: They also have cycled water available, so I can replace 1/4 of the water in this tank with cycled stuff.

 

[Rocksor]

The store has mature filter media I can buy. They claim that plus the bacteria I already dosed it with should do the trick. I have a filter rated for a 70 gallon on this 45, so it'll blast the water through that media hella fast. Thoughts?

You can get the mature filter media, but you would should still do a fishless cycle with pure ammonia. It's a lot less work than doing a fish in cycle, especially with a fish you want to keep. With a fish in cycle, you have to test everyday, and do enough water changes everyday to keep it safe.

 

[Ponera]

What tests should I be doing every day? This kit has like 8 different ones.

 

[esoxlucius]

If you know exactly what you're doing you can do a fish in cycle with the bare minimum, if any, stress to the fish. It involves careful monitoring of parameters and knowing just when to do partial water changes.But you're not experienced at the fish in method. Rocksor has rightly advised against adding the bichir for this reason, too much stress on the fish.

You are better off either going down the ammonia route (dosing ammonia) or getting some more sacrificial fish to get your cycle started. First you will notice a positive ammonia reading on your kit, nitrite and nitrate will be 0ppm at this point. Then your nitrite will start to show and as soon as it does, your ammonia will subside. Then you will start to get a positive on the nitrate, at which point the ammonia should be 0ppm and your nitrite should subside. Then your nitrate will gradually rise and rise and rise until you do a water change to reduce it. That's basically your cycle in a nutshell.

It is the beginning of the cycle when the ammonia and nitrite are present which makes it very difficult doing a fish in cycle because the ammonia and nitrite are so toxic.