Need to rescues some figure 8 puffers

The university my son goes to is about to kill off a bunch of figure 8 puffer fish because the professor that was keeping them was fired.
We want to try and rescue them.
My question is this:
I currently have a 75 gal tank with 2 blue kenyis and 2 yellow labs in it. There are slots of rocks and hiding places.
Can I place a puffer or two in this tank? If so should I convert it to a more brackish water. I’ve read that that shouldn’t hurt the 4 current residents if I do it right.
Your help is appreciated.

 

I dont know about the fish but there's no need for brackish water, ist a shame to kill them I'm sure a lfs would take them

 

So the puffers would be ok in normal (not brackish) water?

 

yes they will be fine, they actually prefer freshwater in in my experience. just watch out for aggression

 

Do you have any LFS near you? I would try contacting them and see if they would take them. Even a petco or petsmart is better than killing them.

 

From what I’ve heard from YouTube videos and articles figure eights tend to have more diseases when not in brackish water and in the wild some even move into full saltwater

 

Do you have any LFS near you? I would try contacting them and see if they would take them. Even a petco or petsmart is better than killing them.

Unfortunately not. He’s in the mountains of Pa. not even a McDonalds near him.

 

I have written an article on another post, so this will be a repost, but I will add information prior to that.

I currently keep figure 8 puffers, along with many other types of puffers, I have a good idea of their care.

Figure 8 Puffers Do NEED Brackish, but low end. I will explain further down in the repost.

They will not pair with your cichlids. Think of puffers as little little water balloons with razor blade teeth and a passive-aggressive attitude. Cichilds would tear them apart, but a puffer can do a lot of damage too. Its not a good combo, that's why most puffers don't do well in community tanks.

Outside of temperament, figure 8's need low end brackish water (1.002-1.006SG, using marine salt!). Cichlids need freshwater, but very hard freshwater. These puffers will due alright in freshwater for a bit, but they become prone to disease long term. The extra minerals in the salt is what the puffers need to stay healthy and strong.

Figure 8's would do great in a 75, the general rule of thumb for them is 1 per 15 gallons. I have 6 in a 40B, but they are all small and happy. I never see any aggression. It really depends on each fish, they all have their own personalities.

Below is a pretty comprehensive idea of what brackish water entails. Not bad, but somewhat of an oddity to care for.

Start of Repost:

Well, I can answer your questions regarding brackish water and F8 Puffers. I am sure that some of this info is will be redundant, but you didn't really list what you know, so I will try to be comprehensive.

The thing with brackish water is that its not something many do. Say 75% of people have mainly freshwater and 25% have saltwater. Brackish is like a 0.01% of people have it. It may not be that low, but you can kinda separate it into two groups. Full fresh (1.000SG) up to 1.005 SG is pretty close to freshwater to a point where you can kinda work with it like freshwater. 1.015 SG to full marine (1.026SG) is more like saltwater, so you can look at it more like that. The fuzzy area of 1.006 to 1.014 is really difficult. There aren't many plants you can grow, corals are a no go, and all around its just kinda "eh it alright" in that range. Ask me how I know.

Most fish will end up becoming either low-end brackish, like your F8 Puffer, or move to high end or full marine.

With this out of the way I can explain transitioning. The main concern here is your nitrogen cycle bacteria. They can really only handle about a swing of 0.002 per week, or about 0.001 per every 3 days. The best way to go about this is to work out the math of roughly how much salt you will need to achieve the goal salinity.

For F8 Puffers, they like salinity about 1.002-1.010 long term. Anywhere in there, and you're golden forever. The easiest by far is to keep them about 1.005 +/-0.002 salinity, so when you do waterchanges you don't have much to worry about replacing or loss of salinity.

For salt you want any saltwater tank salt. Don't waste your money on reef salt, its got extra minerals that you really don't need. Instant Ocean works just fine, and its pretty cheap. You HAVE to use a marine salt, regular table salt or aquarium salt does not contain the correct minerals for brackish/marine fish.

The best mindset for brackish tanks is to think of them as freshwater, but with salt added, as that is basically what they are.

Anytime you are playing with salt, you want to get a tool to measure salinity. You can get a simple hydrometer for about $10 or less, which they work good if you make sure to tap all the air bubbles out and rinse them with freshwater between uses.

You can also use a refractometer, but a good one can cost $50+, and there's a lot of debate as to what the best is.

I use a Hanna Salinity checker pen, its pretty easy, but I paid $80 for it, and I only got it because I have a pico reef tank which I want to easily measure salinity in there for stability reasons.

Honestly, I find hydrometers to be reliable and cheap. My go-to in this situation. With brackish, you really don't need to be super exact.

(I use a python) To dissolve the salt, always do it in a bucket outside of the tank. Putting salt directly into the tank can chemically burn anything it touches as it dissolves. I put the amount I need into a bucket, then use the nozzle on my python to mix it. Use warm water as warmer water dissolves things much faster.

The general synopsis for mixing salt is 1/2 Cup is about 1.026SG per 1 gallon of water.
With some simple math, we can figure out some calculations to dilute that to useful amounts for our purposes.

1 Cup=1.026 per 2 Gallons
1 Cup=1.013 per 4 Gallons
1 Cup=1.007~ per 8 Gallons
1 Cup=1.004~ per 16 Gallons

I think you can see the pattern. 1 Cup is pretty eyeballer math here, so always measure the salinity in your tank after its added. Remember, it is easier to add salt rather than take it out. It costs money too lol.

If I were starting a 20 gallon tank, I would probably put in about a heaping 1/2 of salt just to give it a little bump, then later in the week add more salt.

Also note- evaporation does not remove salt. Always top off with freshwater!

That's a pretty comprehensive list of 'good to know' things for brackish water, but I will continue with livestock.

I am sure you know with F8 Puffers that they are brackish, and they can tolerate a wide range of salinities. The like low end the best. 1.002-1.006 is the sweetspot for them. I have done some extensive research on them, so it is to note that prior to the breeding season they go to high end brackish waters (1.018~) and then return to pure freshwater to breed, but for normal living, they do good in the low end as I have stated. They do alright in higher end salinities, but I wouldn't keep them there forever. A good healthy puffer can handle salinity change pretty well. I wouldn't really worry about slight inconsistencies in salinity too much as in the wild they can swim from full sea water to full fresh within a day if they choose due to their environment.

When it comes to planting a tank, at the lower salinities you are in (some) luck. Plants like:
Java Fern
Java Moss
Valsinaria
Some Anubias
A few select crypts
Anarchis
Moneywort
Crinums

With plants it is important to transition them into brackish, much like your bacteria that you will be doing. Another thing to note is that though a plant is thought to be 'brackish safe' it may not make it. The common saying is that 'your mileage may vary' in this situation, so keep that in mind.


If you have any other questions feel free to message me, I would be happy to answer any other questions!

 

If you are keeping the cichlids in very hard water, that wouldn't be too bad for the puffers; the extra minerals in the water will play a similar role to the salt to help the puffers osmoregulate. You could add a little marine salt too if you want.

The problem is the cichlid aggression; if you put the puffers in there and see them being bullied, you could divide the tank with a divider (you can make DIY dividers easily) to keep them at least until you can set up a new tank or find a new home for them.

Anything you can do will be better than them being flushed down a toilet.