diff --git a/lib/exchange/trocador/trocador_exchange_provider.dart b/lib/exchange/trocador/trocador_exchange_provider.dart
index 18ea27895..6babc8e94 100644
--- a/lib/exchange/trocador/trocador_exchange_provider.dart
+++ b/lib/exchange/trocador/trocador_exchange_provider.dart
@@ -160,8 +160,8 @@ class TrocadorExchangeProvider extends ExchangeProvider {
         'ticker_to': to.title.toLowerCase(),
         'network_from': _networkFor(from),
         'network_to': _networkFor(to),
-        'amount_from': amount.toString(),
-        'amount_to': amount.toString(),
+        if (!isFixedRateMode) 'amount_from': amount.toString(),
+        if (isFixedRateMode) 'amount_to': amount.toString(),
         'payment': isFixedRateMode ? 'True' : 'False',
         'min_kycrating': 'C',
         'markup': '3',