---
product_id: 725604801
title: "Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear)"
brand: "wacker"
price: "€ 30.65"
currency: EUR
in_stock: true
reviews_count: 5
category: "Wacker"
url: https://www.desertcart.nl/products/725604801-wacker-121-professional-aquarium-fish-tank-silicone-sealant-small-to
store_origin: NL
region: Netherlands
---

# FDA-approved, fish-safe formula 100% waterproof & water-resistant 310ml high-performance sealant Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear)

**Brand:** wacker
**Price:** € 30.65
**Availability:** ✅ In Stock

## Summary

> 🐟 Seal the deal with Wacker 121 — where strength meets fish-safe perfection!

## Quick Answers

- **What is this?** Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear) by wacker
- **How much does it cost?** € 30.65 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.nl](https://www.desertcart.nl/products/725604801-wacker-121-professional-aquarium-fish-tank-silicone-sealant-small-to)

## Best For

- wacker enthusiasts

## Why This Product

- Trusted wacker brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Long-Term Durability:** Resists cracking, shrinking, and yellowing even under constant water pressure for years of worry-free use.
- • **Versatile & Reliable:** Perfect for glass, plastics, ceramics, and more—trusted by aquarium pros for over 20 years.
- • **Aquatic Life Friendly:** FDA-approved, non-toxic sealant ensures a safe, healthy environment for your fish and aquatic pets.
- • **Fast, Precise Application:** Smooth, odorless formula cures quickly for clean, professional-grade seals every time.
- • **Unmatched Aquarium Strength:** Engineered in Germany for superior bonding and gap filling on tanks from small to monster-sized.

## Overview

Wacker 121 is a premium German-made silicone sealant designed specifically for aquarium construction and repair. With FDA approval ensuring safety for aquatic life, it offers exceptional waterproofing, high strength, and long-lasting durability. Ideal for tanks of all sizes, this odorless, fast-curing sealant guarantees professional-grade, watertight bonds trusted by aquarium experts worldwide.

## Description

For over two decades, aquarium professionals have trusted Wacker 121 to securely seal monster-sized aquarium glasses. This high-performance silicone sealant provides unbeatable adhesion, ensuring a watertight and durable bond for large custom aquariums. Ideal for both freshwater and saltwater setups, Wacker 121 is formulated to resist cracking, shrinking, and yellowing over time, even under constant water pressure. - *Superior Strength:* Designed to withstand extreme aquarium sizes and volumes. - *Reliable & Long-lasting:* Decades of proven use in professional aquarium setups. - *Safe for Aquatic Life:* Non-toxic, fully aquarium-safe once cured. - *Easy Application:* Smooth application for clean, precise seals.

Review: Perfect for aquarium. Settles well. But give it 3 to 4 days to settle.
Review: Great product, dry instantly and very strong bond. My 400L aquarium seems pretty strong with this. Even you can't see any wobble of Glass when pulls or push like other silicon glues. But you need to carefully apply this one. Highly professional. I had used 2 bottle. After that i bought another astral brand silicon one from local shop, then only i realised about the quality of this wacker product, it's 100% greater than any other product in the market. The astral silicon i brought from the shop had a worst smell also it takes more than 24 hrs for dry. And also not having water holding capacity. But this one is great. Only cons i had was they don't sell smaller ones. If i need a 50ml or 100ml i have no choice for choosing this one. Because this product can't be stored for long after the seal broken.

## Features

- ✔️ PREMIUM GRADE ---> Made in Germany, Wacker 121 is a high performance silicone sealant designed for strong Bonding, Gap Filling & Repair of aquarium tanks, fish tanks and other glazing applications. Suitable for small to large size tank construction.
- ✔️ FDA APPROVED ---> FDA approved for fish and other aquatic animals. No toxins in it, safe and fish friendly.
- ✔️ FEATURES & BENEFITS ---> Excellent Long-term water resistance *★* Suitable for glass, plastics, ceramic products, and more *★* High strength, high toughness, high viscosity *★* Fast curing speed *★* Suitable for objects under water pressure *★* Excellent mechanical properties *★* Usage for wide variety of Glazing & Industrial applications
- ✔️ ENVIRONMENTAL ✔️ ODORLESS ✔️ WATERPROOF ✔️ HIGH-QUALITY

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B08KGVHJJ8 |
| Best Sellers Rank | #59,148 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #143 in Silicone Sealers |
| Item model number | WCK121 |
| Manufacturer | Wacker |
| Product Dimensions | 4.9 x 6.3 x 9.3 cm; 420 g |

## Product Details

- **Brand:** Wacker
- **Colour:** Clear/Transparent
- **Item form:** Paste
- **Material:** Silicone
- **Special features:** Non Toxic, Strong

## Images

![Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear) - Image 1](https://m.media-amazon.com/images/I/410-A9QCDCL.jpg)
![Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear) - Image 2](https://m.media-amazon.com/images/I/51-7mLb8NQL.jpg)
![Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear) - Image 3](https://m.media-amazon.com/images/I/613gvPZhUCL.jpg)
![Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear) - Image 4](https://m.media-amazon.com/images/I/618rQczFfsL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by P***S on 26 December 2025*

Perfect for aquarium. Settles well. But give it 3 to 4 days to settle.

### ⭐⭐⭐⭐⭐ Review
*by A***Q on 7 March 2024*

Great product, dry instantly and very strong bond. My 400L aquarium seems pretty strong with this. Even you can't see any wobble of Glass when pulls or push like other silicon glues. But you need to carefully apply this one. Highly professional. I had used 2 bottle. After that i bought another astral brand silicon one from local shop, then only i realised about the quality of this wacker product, it's 100% greater than any other product in the market. The astral silicon i brought from the shop had a worst smell also it takes more than 24 hrs for dry. And also not having water holding capacity. But this one is great. Only cons i had was they don't sell smaller ones. If i need a 50ml or 100ml i have no choice for choosing this one. Because this product can't be stored for long after the seal broken.

### ⭐⭐⭐⭐ Review
*by N***A on 31 May 2025*

Very nice Product, bonding between two parts too good

## Frequently Bought Together

- Wacker 121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear)
- BIONIX Freshwater Master Test Kit (200 Test).

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*Product available on Desertcart Netherlands*
*Store origin: NL*
*Last updated: 2026-02-19*