Hahnel knew it...

The history of aquarium keeping is an intimate mix of exotic fishes, equally exotic locales, interesting practices, and amazing people. If you go back into the history of our hobby, you're likely to encounter a few names that transcend both time snd geography: Axelrod, Baensch, LaCorte, Fenner, and a guy from New York (via Germany) named Paul Hahnel. 

Often called the "Father of the Fancy Guppy", Hahnel is considered one of the giants of the aquarium hobby, having pioneered the technique and disciplines which helped make the fancy guppy one of the world's most popular and beautiful fishes.

Hahnel and his contemporaries were pioneers, but they were not scientists in the traditional sense. Rather, hobbyists such as Hahnel applied careful observation, discipline, patience, and a healthy dose of common sense into their technique. This is a set of characteristics which has not only distinguished great hobbyists from "average" hobbyists for generations, it helps advance the hobby.

They shared this knowledge freely.

Some of my fave quotes from this guppy legend included stuff like, "Just feed good live and dried food when you pass by your tank from the left, and siphon out 10% of the water when you pass from the right.."

Obviously, this is sort of metaphoric, but the idea rings clear through the decades: Feed your fishes well, and change the water on a regular basis. In other words, be consistent in both husbandry and maintenance. Observe.

And it's really that simple. It's about two key factors in aquarium keeping. This idea of keeping our aquarium water as low in metabolic compounds as possible, while simultaneously feeding our fishes with the most nutritious foods possible as often as possible.

Funny, guppies and guppy breeders sort of formed a "through line" in my fish-keeping pedigree...

For me, growing up in a house full of guppy tanks (My dad was a big fancy guppy fan), the names that came up often were the legendary guppy breeders of the day- Paul Hahnel. His books were all over my dad's fish library, so it was only natural that I'd end up reading them as a kid.

And of course, there was the well-worn copy of the William T. Innes classic, "Exotic Aquarium Fishes"- the book that I literally read a thousand times...cover to cover. Memorized every species name, could quote some of his charming passages about their care, and about stuff as esoteric and "fish-geek-precious" as his discussions on waking up very early in the morning to net Daphnia for fishes off of local ponds. I can still quote the passage that was the "mantra" for the working fish geek:

"Future generations may smile at our working hours, but this allows the tropical fish enthusiast to be at his salaried position by eight..."

I remember haunting the local pond, collecting fairy shrimp and mosquito larvae (which endeared me to my mom to no end) before school, inspired largely by that passage!

In fact, Innes' book had a great picture of one of my all-time favorite fishes, Crenuchus spilurus, the "Sailfin Characin", which I finally acquired after a lifetime in the hobby. It was a huge event for me...

My copies of these books were so beaten up that you could barely open them without pages falling out. I read 'em over and over and over...

These books, written decades before I was even born, and the lessons of people like Hahnel, Innes, and LaCorte, were still the backbone of my "fishy education." And the interesting thing about these old books- and much of the advice preferred in them- is that they stand the test of time. Most of this stuff is fundamental husbandry and common-sense concepts related to the selection, care, and breeding of fishes.

Sure, some of the names have changed, and some things have become more common, like breeding Discus, which in Innes' 1939 edition, was being hailed as one of the greatest tropical fish achievements in history..which, when you think of it in the context of the era...was true.

And then, there was the great Rosario La Corte- one of my favorite all time fish hobbyists. His little paperback book, "Enjoy The Tetras", is pretty much the "vector" for my lifelong love of these fishes. 

He bred hundreds of species of fishes, wrote about them tirelessly in books and magazines, and freely shared his trials and tribulations in grand fish-geek style. I recall in 2012, I was in the New York area and was invited to a meeting of the Long Island Killifish Association, where he was there! At the time, I was pretty much at the top of my "Reef game", fish-geek-star wise, a featured speaker at every major reef conference, clubs worldwide, and an author in online media...Yet, mindful of my pedigree, I was absolutely like a 13-year old girl about to meet her fave TikTok star!

I remember how excited and nervous I was to meet the legend in the flesh.

And you know what? He didn't let me down. He was one of the nicest, most humble fish guys I ever met, and took the time to talk with me about who-knows-what (I think I must have simply repeated "I've read all of your books-like 20 times..." over and over again.), and lived up to his legendary status!

And of course, no other hobbyist, past or present, has ever had the amazing and complete influence on me that my father did. He literally started me with a bowl of fishes when I was 3, and I haven't looked back since. He passed away a few years back, but he influences me every single day.

My dad knew something that was pretty remarkable: If you have a passion, share it with your children. Teach them what you know, nurture their dreams, answer their questions, and encourage them in every way.

Give your son or daughter their first fishbowl, nano-tank, baby guppies. Allow them to feel the excitement when they add that new Tetra, find that cool Angelfish they've been looking for, pick kill eggs from a spawning mop for the first time, or create that perfect aquascape. 

Embrace their geeky enthusiasm. 

And that's what parents who are fish geeks do. It's what fish geeks who just happen to NOT be parents do. It's what fish geeks in general do!

In every field of endeavor, we have our influencers, thought leaders, and yes- legends. People who, through action and thought, have positively influenced the culture and technique of what we do. The tropical fish hobby is no different- except that at the end of the day, most of the key influencers and even the "legends" are gracious, humble, and just good-old fish geeks, like you and me. They have working fish rooms, spill water on the floor, and make all sorts of mistakes...and laugh about them!

And they all carry with them the knowledge borne of effort, enthusiasmm, hard work, and patience. There are no real shortcuts in this hobby- no ways to "beat the system"

There words and lessons resonate across time; transcending eras and generations- and ring as true as they did when they were first written...Much of it simple, concise, and easy to accept.

How funny that the most simple advice I've ever received has guided my aquatic passions far more than some of the complex directives I've been given by well-intentioned aquarists over the years.

Or is it?

We all can learn from the body of knowledge accumulate in the decades before we ever had an aquarium. These are ideas- a culture- which guides everything we do. Sharing our experiences, reaching out to fellow hobbyists, and just talking- has never been more important than it is now. Keep no secrets.

So I guess my one "plea" to all of you crazy-cool fish expert/"obsessionistas" would be to reach out across the aisle- to poke your head over the fence- and share some of your amazing expertise and experience within your specialty to others working in different areas. This will ensure not only that your hard-won information and ideas are not confined only to your specific area of obsession- it will perhaps foster breakthroughs in other hobby specialty groups.

And some of those breakthroughs might just be the key to the long-term well-being of the hobby as a whole, and to sharing, educating about, propagating, and protecting the fishes- and habitats of the world -which so desperately need our attention.


It's what Hahnel knew. It's what every hobbyists knows.

Stay collaborative. Stay open-minded. Stay passionate. Stay generous...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Scott Fellman
Scott Fellman


6 Responses

Patrick Doyle
Patrick Doyle

November 28, 2022

Dear Scott,

Not sure how to tell you how much your article meant to me. I decided to search for any mention of Mr. Hahnel and found your exceptional article.

I grew up in New Rochelle, NY and I’m 68. As a young boy my father Jim Doyle set up (20) 5 gallon glass commercial mayonnaise jars as fancy tail guppy breeding tanks he was given for free from a local deli, in my bedroom. My dad was a Harvard and Purdue Graduate mechanical engineer who invented the aerosol valve, child guard safety caps and many more. He took a serious commercial interest in raising fancy tail guppies and worked with and sold to Mr. Hahnel some of my his fancy guppy stock. Dad had breeding charts and I remember him being so excited when he sold his first breeding pair for $25.00 (early 1960’s). I was eight years old and had 20 bubbling displays of some of the most beautiful fancy tails in my bedroom! To this day I love the sound of an air stone! I read every magazine you pictured and had not thought about them till I read your heart-warming article. Thank you for such a beautiful tribute to Mr. Hahnel.

With respect,
~Patrick Doyle


Joseph Ferdenzi
Joseph Ferdenzi

November 05, 2022

Scott, this is an excellent article. I thoroughly enjoyed it. With the constant turnover in the hobby, it is little wonder that many of the great hobbyists of the past are now largely forgotten. Rosario LaCorte, while no longer breeding fish, is still active in the hobby. You can see a recent interview of him on the Amazonas Magazine YouTube channel. I also think you would find my YouTube lecture on the History of the Greater City Aquarium Society, which is celebrating 100 years of existence, to be of interest to you.

Scott Fellman
Scott Fellman

March 05, 2021

Hi Michael!

Thanks for going this a read. Would absolutely LOVE to have you share your stories and secrets…priceless knowledge that needs more exposure in this “instant gratification” era. Feel free to shoot me an email (tanninaquatics@gmail.com) and we can have you either guest blog or perhaps even appear on “The Tint” podcast sometime to share your stories!

Looking forward to hearing from you!


Michel Bookbinder
Michel Bookbinder

March 04, 2021

Hello! I had a 400 tank tropical fish hatchery in the Bronx (NYC, 1961-1972). Raised Angel Fish (52 breeding pairs), Golden Lyretail Panchax, Emperor Tetras, Prize Winning Bettas, etc. Have many stories. Grew up in Jamaica, Queens. My neighbor was the famous Walter Klaus. Visited Paul Hahnel in his home in the late fifties. Met his family and his cat. Would like to share my stories and my “secrets”. Mike

Scott Fellman
Scott Fellman

October 03, 2020

Thanks, Jack!

There is so much wisdom to be had by reviewing the work and teachings of our hobby forefathers. In fact, many of the things we might view as citing edge today were actually attempted (with the technology and knowledge of the day) by some of these guys many decades ago. It’s amazing to look back at our hobby heritage and not only see how fr we’ve come- but how much we could learn from the efforts of those who came before us in the hobby!

Jack Agliata
Jack Agliata

October 02, 2020

Someone posted on one of my discus Facebook sites just today about pioneers who have made the hobby what it is today like Axelrod and Wattley and Amano. I added for consideration Paul Hahnel and attached your recent article. Unfortunately Hahnel is almost forgotten today except for kids like me (and no doubt your dad) who grew up in the Bronx in the 50s! Great article. THANKS

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