Unusual Aquarium Ad – Thermocon Sign and Article

A rare German advertising sign and article for the “Thermocon” heated aquarium. Sold by  A. Glaschker of Leipzig, Germany around 1909. The aquarium was made in order to insert a kerosene lamp underneath in order to heat the aquarium.

Many collectors of aquarium literature do not pass up collectible items they come across that are not made of paper. These can include food tins, club badges, calendars, and other items. However, enamel aquarium advertising signs are rare—to date, the only one I have come across is the one depicted on the cover.

The company A. Glaschker hardly needs an introduction. It was one of the most renowned aquarium dealers of the first half of the 20th century, initially based in Leipzig and later in Berlin. Their catalogs are sought-after collectibles because they provide insights into the aquaristic practices of the time, including fish, equipment, plants, and aquariums. 

Like many aquarium companies of that era, Glaschker also brought its own products to market, such as the Thermocon aquarium. The special feature of this aquarium—which it shared with the much-advertised ‘Ideal’ by the Paetzig company—was the heating cone inside the aquarium. Unlike the heated base plates found in many other aquariums, the hot air would rise through the cone and heat the aquarium more evenly. This feature is also clearly visible in the illustration.

This illustration on an enamel sign is indeed unusual and rare. These signs were undoubtedly intended to be hung in aquarium shops that sold the ‘Thermocon.’

The sign measures approximately 60 x 40 cm. The enamel is in excellent condition for its age. The sign certainly did not hang outside and was carefully mounted, as there are almost no chips around the mounting holes. There is also no rust visible.

As for its age, the Thermocon aquarium was available as early as 1904. A clue to its age comes from the 1910/11 catalog, which naturally features the Thermocon. The depiction of the ‘old’ Thermocon matches the sign exactly (composition of the fish). Therefore, the sign was likely produced in 1909 or earlier, by the company Robert Müller from Fürth. This company can be found with some signs on the internet (usually advertisements for local breweries), but unfortunately, there is no further information available about the company itself.

It is certain that not many of these signs were produced, as the shops had to stock the Thermocon. Perhaps the one depicted here is the last surviving piece and thus unique. It’s wonderful that it could be documented here. Special thanks go to the Castellum antiquarian bookshop (please see their ad on the back cover).