---
product_id: 725604801
title: "121 Professional Aquarium, Fish Tank Silicone Sealant | Small to Large Tanks | Bonding, Gap Filling & Repair | Safe for Fish (310ml - Clear)"
brand: "wacker"
price: "$29.49"
currency: USD
in_stock: true
reviews_count: 5
category: "Wacker"
url: https://www.desertcart.us/products/725604801-121-professional-aquarium-fish-tank-silicone-sealant-small-to-large
store_origin: US
region: United States of America
---

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

**Brand:** wacker
**Price:** $29.49
**Availability:** ✅ In Stock

## Summary

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

## Quick Answers

- **What is this?** 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?** $29.49 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/725604801-121-professional-aquarium-fish-tank-silicone-sealant-small-to-large)

## 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

- • **Versatile & Reliable:** Perfect for glass, plastics, ceramics, and more—trusted by pros for over 20 years in aquarium construction.
- • **Aquatic Life Approved:** FDA-certified non-toxic sealant ensures a safe, toxin-free environment for your fish and aquatic pets.
- • **Fast & Flawless 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.
- • **Built to Last Under Pressure:** Resists cracking, shrinking, and yellowing even under constant water pressure—durability you can trust.

## Overview

Wacker 121 is a premium 310ml silicone sealant made in Germany, designed specifically for aquarium construction and repair. FDA-approved and non-toxic, it offers superior adhesion, fast curing, and long-lasting waterproof seals that withstand high water pressure without cracking or yellowing. Trusted by professionals for over two decades, it’s ideal for both freshwater and saltwater tanks, ensuring a safe and durable environment for aquatic life.

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

## 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 | #88,157 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #213 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

![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)

## Customer Reviews

### ⭐⭐⭐⭐⭐ 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 P***S on 26 December 2025*

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

### ⭐⭐⭐⭐ Review
*by H***H on 31 January 2026*

“i build 4 feet height 2 feet lenggt tank. The gum is super strong, but it’s very hard to use. It dries very fast—within about 10 minutes it starts getting hard—but once set, the gum is very strong.”

## 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).

---

## Why Shop on Desertcart?

- 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016
- 🌍 **Shop Globally** — Access 737+ million products across 21 categories
- 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price
- 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members)
- 🔒 **Secure Payments** — Trusted payment options with buyer protection
- ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews

**Shop now:** [https://www.desertcart.us/products/725604801-121-professional-aquarium-fish-tank-silicone-sealant-small-to-large](https://www.desertcart.us/products/725604801-121-professional-aquarium-fish-tank-silicone-sealant-small-to-large)

---

*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-03-19*