"55g with 1x per wk WC, Discus stock levels can be 15 to 18 adults"

[Oxboy]

So I'm reading the blog entries at Macsdiscus:

https://macsdiscus.com/discus-fish-blog/

Mostly really good stuff. In fact, there is another recent thread in this forum mentioning his expertise. But there is one huge headscratcher found within: In the excerpt below, he discusses stocking levels. Yes, he's been doing this a long time, but what do you guys think of this advice?

I am asked this question often and before I give an answer, I always ask how often the person changes the water and cleans the tank. Getting the answer to this question is important for accurate feedback. Aquarium population and cleaning on a regular program will determine how many Discus fish can be safely added to an aquarium.

Discus fish belong to the freshwater South American cichlid family and therefore display a natural cichlid pecking order. I have found that adding more Discus fish to the tank calms their behavior by diluting this pecking order. If one cleans their tank and gravel once every 5 to 7 days on a regular basis, completes a 25% water change, and does not overfeed, you can stock a 100-gallon tank with 35 to 40 adult Discus fish. This stock level will result in your Discus fish growing evenly. There will be minimal pecking at feeding time and all the Discus fish will get their share of the meal. On the other hand, if one only wants to clean and change 25% of the tank water every month, then I would suggest following the one fish per 10-gallon rule and therefore stock with only 10 Discus fish. This stock level can lead to a severe pecking order resulting in uneven growth due to the dominant Discus fish getting all the food, growing faster, and eventually dominating the rest of the Discus fish in the tank. This is not good for your overall Discus fish community.

You can use the above formula to figure your comfort level and how much work you want to devote to aquarium maintenance and your particular tank size. For easy reference, if your setup is greater or less than 100-gallons you can do the math as follows.

150-gallon with once per week water changes Discus fish stock levels can be 55 to 60 adults, or once per month cleaning 15 adults.

55-gallons with once per week water changes Discus fish stock levels can be 15 to 18 adults, or once per month cleaning 5 to 6 adults.

30-gallons with weekly water changes Discus fish stock levels can be 6 to 7 adults, or once per month cleaning 2 to 3 adults.

The above formula is for Discus fish, any other varieties of small fish which are also in the tank do not count. Collectively the smaller fish will not put out a significant amount of waste.

[danotaylor]

It's terrible advice

[LizStreithorst]

Sounds to me like he wants to sell a bunch of fish.

[coralbandit]

Plus one with Liz !
My take on it is not as polite though ;


I keep 100 rams in a 40b but I would never tell a customer to do it .
I guess some will do or say anything for a sale ? The fish industry is basically more corrupt then insurance or banks IMO .They love to make you think you failed and then get you to pay again IMO .
Sure you can have 20 rams in your 20g that will be $400 thank you !
His water change advice is criminal IMO . 25% a week ! Again some will say or do anything to make a sale ….

[BrendanJ23]

Oh my god. That’s insane. Apart from all the othe factors, 60 adults in a 150 gallon, they wouldn’t be able to move!

[Willie]

My previous post was not a general statement.

Kenny is good, but I've also gotten high quality fish from many other Simply vendors. Without rehashing all the reasons that have been posted previously, I highly recommend you stay with these businesses. Everyone else is a huge crap shoot.

Willie

[peewee1]

I do now and have for the past 2 years keep 5 to 6 Discus in 30 gallons with weekly water change of 100% spread over 7 days. It works for me. I did not do his math on the 55 gallon tank but I would not be afraid of 10 to 11 Discus using the same approach as the 30 gallon. I have stated several times from my experiences breeding Discus 30 years prior that I did not know anything about fish per gallon, foods, or chemical balances, or water changes. I would be old school, which Mac seems to be as well.

[LizStreithorst]

Plus one with Liz !
My take on it is not as polite though ;


I keep 100 rams in a 40b but I would never tell a customer to do it .
I guess some will do or say anything for a sale ? The fish industry is basically more corrupt then insurance or banks IMO .They love to make you think you failed and then get you to pay again IMO .
Sure you can have 20 rams in your 20g that will be $400 thank you !
His water change advice is criminal IMO . 25% a week ! Again some will say or do anything to make a sale ….

lol. You have said exactly what I might have said when I was a hot head, around 10 years ago but I would have been even less polite. I'd have been offencive. I have no idea why I mellowed since then. You made me miss my old trouble making self.

[dspeers]

Peewee, you are at 5 gallons/fish and changing ~15% water every day

Mac is recommending the equivalent of 4-5% water change per day depending on whether you do 25% every 5 or 7 days. His monthly recommendations for a 10 gal/fish setup are even scarier. Maybe he meant 250%/month.

Also his ratio at 30 gallons is 5 gal/fish but at 55 gal he recommends 3-4 gal/fish and the 150 <3 gal/fish.....for adult discus.

Is he selling dwarf discus with a full size of 2 inches? Those numbers seem outlandishly crazy to me. Would guess a nitrate level of > 100 if this were tried even with your type of sump filtration.


His reviews have historically been hit or miss, seems to me there are various better options, most of whom are on this site.

[peewee1]

Peewee, you are at 5 gallons/fish and changing ~15% water every day

Mac is recommending the equivalent of 4-5% water change per day depending on whether you do 25% every 5 or 7 days. His monthly recommendations for a 10 gal/fish setup are even scarier. Maybe he meant 250%/month.

Also his ratio at 30 gallons is 5 gal/fish but at 55 gal he recommends 3-4 gal/fish and the 150 <3 gal/fish.....for adult discus.

Is he selling dwarf discus with a full size of 2 inches? Those numbers seem outlandishly crazy to me. Would guess a nitrate level of > 100 if this were tried even with your type of sump filtration.


His reviews have historically been hit or miss, seems to me there are various better options, most of whom are on this site.

Don, thanks. I had not thought past the 30 gallons, which is me. Perhaps the approach with Mac's Discus would be to purchase the fish of your choices and then raise them using the 1 fish for 10 gallons rule of thumb. I'm going to get a 50 next tank in order to make room in the 30 gallons for breeding for two who have paired. With that said I would not be opposed to having 7 to 9 fish in that 50 gallon tank. My thought is perhaps his stocking ideas are off but the quality of his product may be as good as any. I would like to try this guy but I am so loyal to Kenny that it would be hard for me to buy from anyone but Kenny.

[peewee1]

Oh my god. That’s insane. Apart from all the othe factors, 60 adults in a 150 gallon, they wouldn’t be able to move!

Perhaps Mac was born and raised in New York City, Delhi, or Tokyo and is used to more bodies per square inch?

[jeep]

I'd like to say what I really think about that advice but the mods would probably delete my comment...

[Iminit]

Wow that’s some strange advice! Is he backing it up? Has he figured out the secret of discus health? So 25% water change once a week and I can keep 40 of his fish and he will restock any that die? Got to be a mistake.

[coralbandit]

lol. You have said exactly what I might have said when I was a hot head, around 10 years ago but I would have been even less polite. I'd have been offencive. I have no idea why I mellowed since then. You made me miss my old trouble making self.

That's funny cause I would have said worse back when I was a hot head also !
I like to say " it only hurts if it is true and what do I know ?"
I don't miss my old self ..I said some stuff that probably was not necessary ..You know you can lead a keeper to water but you can't make them change it !

[CliffsDiscus]

He is not growing out Discus only stocking before selling. Breeder and importer that
advertised since back in the 80s in fish magazines long before internet. I received(e-mail)
at one time by mistake that his Discus shipment was
delayed from an Asian fish supplier.

Cliff