What do I add next

[shramp]

So currently in my 37 gallon tank I have 7 cherry shrimp and 10 Amano shrimp. I initially had 10 of both but 1 died due to getting caught in a filter that I have since removed and 2 others died I am guessing due to a nitrite spike that was probably due to me having to take out the more established filter of the tank. (I did cycle the tank for slightly over a month before adding anything at all and made sure parameters were good and all, taking out that filter just messed things up)

The reason I added shrimp first was because I thought it would be better to add tinier creatures first so they don't get eaten right away and can find hiding spots and whatnot. I wasn't thinking that shrimp are more sensitive to tank conditions than fish and adding them to a new tank probably wasn't a good idea.

I don't want to make that mistake again. What is a hardier fish I can add next? I really want to be able to move these fish I got from my friend into their big tank but I don't want to do it just for them to die once I transfer them. I've grown very attached The ones I intend to put in the big tank w full schools (for the schooling fish) eventually are the orange neon tetra, the ember tetras, the Cory catfish and the Dalmatian Molly. Would any of these be better to add first?? I will of course wait until the water parameters restabilize.

[shramp]

I guess I just don't really fully understand the tank set up process. I get now that my cycle got messed up when my filter was removed and I'm basically back to the nitrite phase and stuck doing a fish in cycle with my shrimp. (After all the effort I went through to do one fishless, ugh) If I manage to re-cycle the tank (which it is going well, nitrites have been decreasing albeit slowly), and get it back to where it was before, will it then be safe to add any fish so long as it's in small amounts at a time? Or do I need to start with a hardy fish still and wait even more time? What is the timeline until I can put in more sensitive fish which apparently all of mine are?

I'm seeing people saying they wait until an established tank is months old with fish before adding things like tetras. But I don't know if my fish will survive for months more in that 5 gallon. Especially the poor lone neon who has no school. Oh man this is tough. Death by stress from overcrowding and lack of schools or death by unstable tank? Fantastic.

[Aiken Drum]

To cycle a tank you need to grow denitrifying bacteria to consume ammonia and nitrite that your tank produces. The bacteria needs an ammonia source to grow colonies sufficient in size to consume all the ammonia and resultant nitrite and turn it into nitrate which typically you remove through your regular water changes.

A fish in cycle uses fish waste as an ammonia source and regular water changes are undertaken to ensure that water parameters are maintained at relatively non toxic levels.

Set up your tank. Make sure everything is running smoothly. Make sure you have used a water conditioner product with any tap water you have put in your tank. Seachem Prime is a water conditioner that will also detoxify some ammonia for a day or two, so is a good choice for a water conditioner while cycling a tank with fish.

You should have a test kit. Preferably a liquid test kit. It should test for ammonia, nitrite, and nitrate.

In ideal circumstances you should be starting a fishless cycle with a low bioload (number of fish). 1 small fish per 10 gallons/40 litres is a good number of fish, but this can be tweaked a little for fish that are social and don’t do well on their own. Ideally a hardy type of fish. You may have fully stocked (or overstocked) your tank before you knew about cycling. In these circumstances, if its not possible to return fish, you will have to make the best of it.

If you haven’t already done so, add your fish. Acclimate them to the water in your tank before doing so.

Feed lightly to start with. Daily as much as is eaten in 2 minutes, or as much as is eaten in 3 minutes every 2 days. You can increase to full feedings if you are confident your parameters aren’t getting too elevated too quickly and water changes don’t become a daily thing.

Start to regularly test the water for ammonia and nitrite. At least daily. Depending on your bioload you could start to see ammonia quite quickly. Nitrite will likely take a little longer to appear.

Your target should be to keep ammonia + nitrite combined no higher than 0.5ppm by changing water whenever your water parameters exceed this target. 0.5ppm combined is a level of waste that is sufficient for your cycle to establish but relatively safe for your fish.

If you see 0.5ppm ammonia and 0.0ppm nitrite (0.5ppm combined) then leave things be. If you see 0.5ppm ammonia and 0.25ppm nitrite (0.75ppm combined) then change 1/3 of the water. If you see 0.25ppm ammonia and 0.75ppm nitrite (1.0ppm combined) then change 1/2 the water. If water parameters get worse than these levels it may require multiple daily 50% water changes to maintain safe water conditions. This is more likely to happen with a fully stocked tank.

Remember to add water conditioner whenever you put tap water in the tank.

Over time the frequency of water changes and amount you need to change to maintain your ammonia + nitrite combined target will reduce. You can also start testing for nitrate and should see this rising. If you are finding the ammonia and nitrite in your tests are consistently low, and you aren’t already fully stocked, you can add a few more fish. It may take a few weeks to get to this point.

Once you add a few more fish, continue to regularly test the water and continue to change water if you exceed the 0.5ppm combined ammonia + nitrite target. With added bioload the frequency of water changes and amount you need to change may increase again until your cycle has caught up. Again once you are consistently seeing low ammonia and nitrite you can add some more fish. Rinse and repeat with testing, water changes, and adding fish when safe to do so until you are fully stocked.

You can then cut back on water changes to control nitrate only. Typically you want to keep nitrate no higher than 40ppm, but I would recommend changing some water every 2 weeks even if your water test says you don’t need to.

A fish in cycle from an empty tank to fully stocked can take several months.

A good way to speed up this process would be to put a small amount of filter media from an established filter into your filter, or get a sponge from an established filter and squeeze it into your tank water. Perhaps you have a friend who keeps fish who could let you have some? This will seed your filter with the bacteria you are trying to grow and speed up the process.

Another option is bottled bacteria like Dr Tims One + Only or Tetra Safestart. These products wont instantly cycle a tank as they claim but in a similar manner to adding established filter media they can seed your filter with the bacteria you are trying to grow to establish your cycle. These products are hit and miss as to whether they work at all, but are an option if established filter media isnt obtainable and may speed up the process from several months to several weeks.

[Aiken Drum]

Follow a fish in cycle properly and there should be minimal risk to your fish.

Of the fish you have, probably the molly is the most hardy, but if you follow the process and keep on top of the required water changes there is minimal risk no matter which order you add then in.

How many fish do you need to move? I would probably just do a big water change to get parameters good and move them all.

[shramp]

OK great that is good to know. I understand cycling I just didn't understand at what point you could add what fish and to what amount lol.

I was given 3 ember tetras, 1 dalmatian molly, 1 Cory, 1 neon orange tetra, 4 redeye tetra, 3 ghost shrimp and a nerite snail in a 5 gallon tank. I want to transfer all but the redeyes, shrimp and snail to my 37 gallon tank. (Redeyes are going in a different tank and inverts are going to stay in the 5 gal).

My initial plan was to first move over the embers and neon (because it attempts to school with them since it is a loner). Then add the Cory and molly once I was sure the tank could handle it. The only reason why I'm hesitant to add the Molly first is she is so dominant/aggressive I'm concerned she will claim the tank and beat up the little ones if I put her in first. But if you don't think that's a concern I could add her and the Cory first. I do think a lot of her aggression is probably due to the cramped space and the other fish would be happy to have her out of their space for a while.

Then after transferring them all I was going to keep the 5 gallon as a quarantine tank for the rest of the fish I plan to add to the tank. I'm a bit confused as to how to best add in schooling fish. Should I just get like 3 at a time?

I should add all of my fish from the 5 gallon right now even though I still have nitrites? I have only just started being able to get the level back down. Won't adding all those fish off the bat cause a huge spike again?

[Aiken Drum]

Them being in an uncycled 37g is better than a cycled 5g as long as you put the work in to keep water parameters safe IMO. Everytime you move fish your cycle will need to catch up with the increased bioload and you could start to see ammonia and/or nitrite. Doing it slowly over a number of weeks is safer for the fish in the 37g but at the detriment of the ones left in the 5g. You have to move them at some point. May as well get it it of the way.

But its your choice. Nobody can tell you "this is how you must do it". I would move then because i know im prepared to do the work to keep things safe and i wouldnt want fish kept in a tiny tank for longer than i had to if i had an option to move them to a more suitable environment.

As said, big water change to bring nitrite below 0.5ppm then whatever changes are needed to keep ammonia + nitrite combined no higher than 0.5ppm. This may mean multiple, daily water changes, but ensures parameters never get to harmful levels.

[shramp]

OK I get what you are saying. I know they are miserable being so cramped. Conditions in their little tank are probably worse than the big one/more fluctuating due to the size and overcrowding anyhow.

[shramp]

Update, I successfully transferred everyone!! I can't wait to get them their full schools. Right now they look so teeny in their huge tank.

[shramp]

So my fish are clearly very stressed in the new space without schools. The embers are doing OK as they at least have a few of them but the Cory and what I now know is a glowlight tetra have been swimming at the glass trying to school w their reflections. I am not too worried for the Cory because it is pretty tough and also doesn't do the glass swimming as constantly as the glowlight who has lost his pretty coloration and just constantly chases his reflection.

I am thinking based on what you said about it not really mattering how many fish you add at a time so long as you monitor and do frequent water changes and wondering if I should just go out and add their schools now. I originally planned to quarantine the new fish but it may not be necessary as I get my fish from a reputable source that takes good care of its stock and are always healthy looking. I also genuinely don't think the glowlight is going to survive the time it takes me to quarantine more glowlights. So I think I will just go out and get them their schools and hope for the best.